drm_irq.c 49.3 KB
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Daniel Vetter 已提交
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/*
 * drm_irq.c IRQ and vblank support
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 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

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#include <drm/drmP.h>
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#include "drm_trace.h"
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#include "drm_internal.h"
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#include <linux/interrupt.h>	/* For task queue support */
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#include <linux/slab.h>
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#include <linux/vgaarb.h>
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#include <linux/export.h>
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/* Access macro for slots in vblank timestamp ringbuffer. */
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#define vblanktimestamp(dev, crtc, count) \
	((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
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/* Retry timestamp calculation up to 3 times to satisfy
 * drm_timestamp_precision before giving up.
 */
#define DRM_TIMESTAMP_MAXRETRIES 3

/* Threshold in nanoseconds for detection of redundant
 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
 */
#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000

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static bool
drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
			  struct timeval *tvblank, unsigned flags);

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static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */

/*
 * Default to use monotonic timestamps for wait-for-vblank and page-flip
 * complete events.
 */
unsigned int drm_timestamp_monotonic = 1;

static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */

module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);

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/**
 * drm_update_vblank_count - update the master vblank counter
 * @dev: DRM device
 * @crtc: counter to update
 *
 * Call back into the driver to update the appropriate vblank counter
 * (specified by @crtc).  Deal with wraparound, if it occurred, and
 * update the last read value so we can deal with wraparound on the next
 * call if necessary.
 *
 * Only necessary when going from off->on, to account for frames we
 * didn't get an interrupt for.
 *
 * Note: caller must hold dev->vbl_lock since this reads & writes
 * device vblank fields.
 */
static void drm_update_vblank_count(struct drm_device *dev, int crtc)
{
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	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	u32 cur_vblank, diff, tslot;
	bool rc;
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	struct timeval t_vblank;

	/*
	 * Interrupts were disabled prior to this call, so deal with counter
	 * wrap if needed.
	 * NOTE!  It's possible we lost a full dev->max_vblank_count events
	 * here if the register is small or we had vblank interrupts off for
	 * a long time.
	 *
	 * We repeat the hardware vblank counter & timestamp query until
	 * we get consistent results. This to prevent races between gpu
	 * updating its hardware counter while we are retrieving the
	 * corresponding vblank timestamp.
	 */
	do {
		cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
		rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
	} while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));

	/* Deal with counter wrap */
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	diff = cur_vblank - vblank->last;
	if (cur_vblank < vblank->last) {
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		diff += dev->max_vblank_count;

		DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
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			  crtc, vblank->last, cur_vblank, diff);
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	}

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	DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
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		  crtc, diff);

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	if (diff == 0)
		return;

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	/* Reinitialize corresponding vblank timestamp if high-precision query
	 * available. Skip this step if query unsupported or failed. Will
	 * reinitialize delayed at next vblank interrupt in that case.
	 */
	if (rc) {
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		tslot = atomic_read(&vblank->count) + diff;
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		vblanktimestamp(dev, crtc, tslot) = t_vblank;
	}

	smp_mb__before_atomic();
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	atomic_add(diff, &vblank->count);
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	smp_mb__after_atomic();
}

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/*
 * Disable vblank irq's on crtc, make sure that last vblank count
 * of hardware and corresponding consistent software vblank counter
 * are preserved, even if there are any spurious vblank irq's after
 * disable.
 */
static void vblank_disable_and_save(struct drm_device *dev, int crtc)
{
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	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	unsigned long irqflags;
	u32 vblcount;
	s64 diff_ns;
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	bool vblrc;
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	struct timeval tvblank;
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	int count = DRM_TIMESTAMP_MAXRETRIES;
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	/* Prevent vblank irq processing while disabling vblank irqs,
	 * so no updates of timestamps or count can happen after we've
	 * disabled. Needed to prevent races in case of delayed irq's.
	 */
	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);

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	/*
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	 * If the vblank interrupt was already disabled update the count
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	 * and timestamp to maintain the appearance that the counter
	 * has been ticking all along until this time. This makes the
	 * count account for the entire time between drm_vblank_on() and
	 * drm_vblank_off().
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	 *
	 * But only do this if precise vblank timestamps are available.
	 * Otherwise we might read a totally bogus timestamp since drivers
	 * lacking precise timestamp support rely upon sampling the system clock
	 * at vblank interrupt time. Which obviously won't work out well if the
	 * vblank interrupt is disabled.
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	 */
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	if (!vblank->enabled &&
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	    drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
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		drm_update_vblank_count(dev, crtc);
		spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
		return;
	}

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	dev->driver->disable_vblank(dev, crtc);
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	vblank->enabled = false;
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	/* No further vblank irq's will be processed after
	 * this point. Get current hardware vblank count and
	 * vblank timestamp, repeat until they are consistent.
	 *
	 * FIXME: There is still a race condition here and in
	 * drm_update_vblank_count() which can cause off-by-one
	 * reinitialization of software vblank counter. If gpu
	 * vblank counter doesn't increment exactly at the leading
	 * edge of a vblank interval, then we can lose 1 count if
	 * we happen to execute between start of vblank and the
	 * delayed gpu counter increment.
	 */
	do {
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		vblank->last = dev->driver->get_vblank_counter(dev, crtc);
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		vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
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	} while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
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	if (!count)
		vblrc = 0;
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	/* Compute time difference to stored timestamp of last vblank
	 * as updated by last invocation of drm_handle_vblank() in vblank irq.
	 */
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	vblcount = atomic_read(&vblank->count);
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	diff_ns = timeval_to_ns(&tvblank) -
		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));

	/* If there is at least 1 msec difference between the last stored
	 * timestamp and tvblank, then we are currently executing our
	 * disable inside a new vblank interval, the tvblank timestamp
	 * corresponds to this new vblank interval and the irq handler
	 * for this vblank didn't run yet and won't run due to our disable.
	 * Therefore we need to do the job of drm_handle_vblank() and
	 * increment the vblank counter by one to account for this vblank.
	 *
	 * Skip this step if there isn't any high precision timestamp
	 * available. In that case we can't account for this and just
	 * hope for the best.
	 */
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	if (vblrc && (abs64(diff_ns) > 1000000)) {
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		/* Store new timestamp in ringbuffer. */
		vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;

		/* Increment cooked vblank count. This also atomically commits
		 * the timestamp computed above.
		 */
		smp_mb__before_atomic();
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		atomic_inc(&vblank->count);
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		smp_mb__after_atomic();
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	}
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	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
}

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static void vblank_disable_fn(unsigned long arg)
{
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	struct drm_vblank_crtc *vblank = (void *)arg;
	struct drm_device *dev = vblank->dev;
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	unsigned long irqflags;
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	int crtc = vblank->crtc;
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	if (!dev->vblank_disable_allowed)
		return;

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	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
		DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
		vblank_disable_and_save(dev, crtc);
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	}
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	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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}

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/**
 * drm_vblank_cleanup - cleanup vblank support
 * @dev: DRM device
 *
 * This function cleans up any resources allocated in drm_vblank_init.
 */
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void drm_vblank_cleanup(struct drm_device *dev)
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{
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	int crtc;
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	unsigned long irqflags;
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	/* Bail if the driver didn't call drm_vblank_init() */
	if (dev->num_crtcs == 0)
		return;

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	for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
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		struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

		del_timer_sync(&vblank->disable_timer);
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		spin_lock_irqsave(&dev->vbl_lock, irqflags);
		vblank_disable_and_save(dev, crtc);
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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	}
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	kfree(dev->vblank);
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	dev->num_crtcs = 0;
}
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EXPORT_SYMBOL(drm_vblank_cleanup);
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/**
 * drm_vblank_init - initialize vblank support
 * @dev: drm_device
 * @num_crtcs: number of crtcs supported by @dev
 *
 * This function initializes vblank support for @num_crtcs display pipelines.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
 */
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int drm_vblank_init(struct drm_device *dev, int num_crtcs)
{
	int i, ret = -ENOMEM;

	spin_lock_init(&dev->vbl_lock);
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	spin_lock_init(&dev->vblank_time_lock);

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	dev->num_crtcs = num_crtcs;

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	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
	if (!dev->vblank)
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		goto err;

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	for (i = 0; i < num_crtcs; i++) {
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		struct drm_vblank_crtc *vblank = &dev->vblank[i];

		vblank->dev = dev;
		vblank->crtc = i;
		init_waitqueue_head(&vblank->queue);
		setup_timer(&vblank->disable_timer, vblank_disable_fn,
			    (unsigned long)vblank);
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	}
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	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
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	/* Driver specific high-precision vblank timestamping supported? */
	if (dev->driver->get_vblank_timestamp)
		DRM_INFO("Driver supports precise vblank timestamp query.\n");
	else
		DRM_INFO("No driver support for vblank timestamp query.\n");

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	dev->vblank_disable_allowed = false;

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	return 0;

err:
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	dev->num_crtcs = 0;
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	return ret;
}
EXPORT_SYMBOL(drm_vblank_init);

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static void drm_irq_vgaarb_nokms(void *cookie, bool state)
{
	struct drm_device *dev = cookie;

	if (dev->driver->vgaarb_irq) {
		dev->driver->vgaarb_irq(dev, state);
		return;
	}

	if (!dev->irq_enabled)
		return;

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	if (state) {
		if (dev->driver->irq_uninstall)
			dev->driver->irq_uninstall(dev);
	} else {
		if (dev->driver->irq_preinstall)
			dev->driver->irq_preinstall(dev);
		if (dev->driver->irq_postinstall)
			dev->driver->irq_postinstall(dev);
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	}
}

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/**
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 * drm_irq_install - install IRQ handler
 * @dev: DRM device
 * @irq: IRQ number to install the handler for
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 *
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 * Initializes the IRQ related data. Installs the handler, calling the driver
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 * irq_preinstall() and irq_postinstall() functions before and after the
 * installation.
 *
 * This is the simplified helper interface provided for drivers with no special
 * needs. Drivers which need to install interrupt handlers for multiple
 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
 * that vblank interrupts are available.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
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 */
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int drm_irq_install(struct drm_device *dev, int irq)
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{
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	int ret;
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	unsigned long sh_flags = 0;
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

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	if (irq == 0)
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		return -EINVAL;

	/* Driver must have been initialized */
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	if (!dev->dev_private)
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		return -EINVAL;

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	if (dev->irq_enabled)
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		return -EBUSY;
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	dev->irq_enabled = true;
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	DRM_DEBUG("irq=%d\n", irq);
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	/* Before installing handler */
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	if (dev->driver->irq_preinstall)
		dev->driver->irq_preinstall(dev);
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	/* Install handler */
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	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
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		sh_flags = IRQF_SHARED;
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	ret = request_irq(irq, dev->driver->irq_handler,
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			  sh_flags, dev->driver->name, dev);
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	if (ret < 0) {
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		dev->irq_enabled = false;
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		return ret;
	}

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	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);

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	/* After installing handler */
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	if (dev->driver->irq_postinstall)
		ret = dev->driver->irq_postinstall(dev);

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	if (ret < 0) {
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		dev->irq_enabled = false;
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		if (!drm_core_check_feature(dev, DRIVER_MODESET))
			vga_client_register(dev->pdev, NULL, NULL, NULL);
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		free_irq(irq, dev);
	} else {
		dev->irq = irq;
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	}
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	return ret;
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}
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EXPORT_SYMBOL(drm_irq_install);
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/**
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 * drm_irq_uninstall - uninstall the IRQ handler
 * @dev: DRM device
 *
 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
 * This should only be called by drivers which used drm_irq_install() to set up
 * their interrupt handler. Other drivers must only reset
 * drm_device->irq_enabled to false.
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 *
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 * Note that for kernel modesetting drivers it is a bug if this function fails.
 * The sanity checks are only to catch buggy user modesetting drivers which call
 * the same function through an ioctl.
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 *
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 * Returns:
 * Zero on success or a negative error code on failure.
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 */
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int drm_irq_uninstall(struct drm_device *dev)
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{
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	unsigned long irqflags;
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	bool irq_enabled;
	int i;
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	irq_enabled = dev->irq_enabled;
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	dev->irq_enabled = false;
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	/*
	 * Wake up any waiters so they don't hang.
	 */
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	if (dev->num_crtcs) {
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
		for (i = 0; i < dev->num_crtcs; i++) {
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			struct drm_vblank_crtc *vblank = &dev->vblank[i];

			wake_up(&vblank->queue);
			vblank->enabled = false;
			vblank->last =
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				dev->driver->get_vblank_counter(dev, i);
		}
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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	}

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	if (!irq_enabled)
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		return -EINVAL;

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	DRM_DEBUG("irq=%d\n", dev->irq);
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	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		vga_client_register(dev->pdev, NULL, NULL, NULL);

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	if (dev->driver->irq_uninstall)
		dev->driver->irq_uninstall(dev);
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	free_irq(dev->irq, dev);
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	return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);

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/*
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 * IRQ control ioctl.
 *
 * \param inode device inode.
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 * \param file_priv DRM file private.
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 * \param cmd command.
 * \param arg user argument, pointing to a drm_control structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls irq_install() or irq_uninstall() according to \p arg.
 */
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int drm_control(struct drm_device *dev, void *data,
		struct drm_file *file_priv)
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{
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	struct drm_control *ctl = data;
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	int ret = 0, irq;
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	/* if we haven't irq we fallback for compatibility reasons -
	 * this used to be a separate function in drm_dma.h
	 */
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return 0;
	if (drm_core_check_feature(dev, DRIVER_MODESET))
		return 0;
	/* UMS was only ever support on pci devices. */
	if (WARN_ON(!dev->pdev))
		return -EINVAL;
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	switch (ctl->func) {
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	case DRM_INST_HANDLER:
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		irq = dev->pdev->irq;

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		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
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		    ctl->irq != irq)
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			return -EINVAL;
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		mutex_lock(&dev->struct_mutex);
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		ret = drm_irq_install(dev, irq);
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		mutex_unlock(&dev->struct_mutex);

		return ret;
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	case DRM_UNINST_HANDLER:
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		mutex_lock(&dev->struct_mutex);
		ret = drm_irq_uninstall(dev);
		mutex_unlock(&dev->struct_mutex);

		return ret;
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	default:
		return -EINVAL;
	}
}

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/**
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 * drm_calc_timestamping_constants - calculate vblank timestamp constants
 * @crtc: drm_crtc whose timestamp constants should be updated.
 * @mode: display mode containing the scanout timings
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 *
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 * Calculate and store various constants which are later
 * needed by vblank and swap-completion timestamping, e.g,
 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
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 * derived from CRTC's true scanout timing, so they take
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 * things like panel scaling or other adjustments into account.
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 */
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void drm_calc_timestamping_constants(struct drm_crtc *crtc,
				     const struct drm_display_mode *mode)
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{
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	int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
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	int dotclock = mode->crtc_clock;
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	/* Valid dotclock? */
	if (dotclock > 0) {
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		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;

		/*
		 * Convert scanline length in pixels and video
		 * dot clock to line duration, frame duration
		 * and pixel duration in nanoseconds:
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		 */
581 582 583
		pixeldur_ns = 1000000 / dotclock;
		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
584 585 586 587 588 589

		/*
		 * Fields of interlaced scanout modes are only half a frame duration.
		 */
		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
			framedur_ns /= 2;
590 591 592 593 594 595 596 597 598
	} else
		DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
			  crtc->base.id);

	crtc->pixeldur_ns = pixeldur_ns;
	crtc->linedur_ns  = linedur_ns;
	crtc->framedur_ns = framedur_ns;

	DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
599 600
		  crtc->base.id, mode->crtc_htotal,
		  mode->crtc_vtotal, mode->crtc_vdisplay);
601
	DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
602 603
		  crtc->base.id, dotclock, framedur_ns,
		  linedur_ns, pixeldur_ns);
604 605 606 607
}
EXPORT_SYMBOL(drm_calc_timestamping_constants);

/**
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 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
 * @dev: DRM device
 * @crtc: Which CRTC's vblank timestamp to retrieve
 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
 *             On return contains true maximum error of timestamp
 * @vblank_time: Pointer to struct timeval which should receive the timestamp
 * @flags: Flags to pass to driver:
 *         0 = Default,
 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
 * @refcrtc: CRTC which defines scanout timing
 * @mode: mode which defines the scanout timings
 *
 * Implements calculation of exact vblank timestamps from given drm_display_mode
 * timings and current video scanout position of a CRTC. This can be called from
 * within get_vblank_timestamp() implementation of a kms driver to implement the
 * actual timestamping.
624 625 626 627 628 629 630 631 632 633 634 635 636 637
 *
 * Should return timestamps conforming to the OML_sync_control OpenML
 * extension specification. The timestamp corresponds to the end of
 * the vblank interval, aka start of scanout of topmost-leftmost display
 * pixel in the following video frame.
 *
 * Requires support for optional dev->driver->get_scanout_position()
 * in kms driver, plus a bit of setup code to provide a drm_display_mode
 * that corresponds to the true scanout timing.
 *
 * The current implementation only handles standard video modes. It
 * returns as no operation if a doublescan or interlaced video mode is
 * active. Higher level code is expected to handle this.
 *
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 * Returns:
 * Negative value on error, failure or if not supported in current
640 641
 * video mode:
 *
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 * -EINVAL   - Invalid CRTC.
643 644 645 646 647 648 649 650 651 652 653 654 655 656
 * -EAGAIN   - Temporary unavailable, e.g., called before initial modeset.
 * -ENOTSUPP - Function not supported in current display mode.
 * -EIO      - Failed, e.g., due to failed scanout position query.
 *
 * Returns or'ed positive status flags on success:
 *
 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
 *
 */
int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
					  int *max_error,
					  struct timeval *vblank_time,
					  unsigned flags,
657 658
					  const struct drm_crtc *refcrtc,
					  const struct drm_display_mode *mode)
659
{
660
	struct timeval tv_etime;
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	ktime_t stime, etime;
662
	int vbl_status;
663
	int vpos, hpos, i;
664
	int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685
	bool invbl;

	if (crtc < 0 || crtc >= dev->num_crtcs) {
		DRM_ERROR("Invalid crtc %d\n", crtc);
		return -EINVAL;
	}

	/* Scanout position query not supported? Should not happen. */
	if (!dev->driver->get_scanout_position) {
		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
		return -EIO;
	}

	/* Durations of frames, lines, pixels in nanoseconds. */
	framedur_ns = refcrtc->framedur_ns;
	linedur_ns  = refcrtc->linedur_ns;
	pixeldur_ns = refcrtc->pixeldur_ns;

	/* If mode timing undefined, just return as no-op:
	 * Happens during initial modesetting of a crtc.
	 */
686
	if (framedur_ns == 0) {
687 688 689 690 691 692 693 694 695 696 697 698
		DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
		return -EAGAIN;
	}

	/* Get current scanout position with system timestamp.
	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
	 * if single query takes longer than max_error nanoseconds.
	 *
	 * This guarantees a tight bound on maximum error if
	 * code gets preempted or delayed for some reason.
	 */
	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
699 700 701 702
		/*
		 * Get vertical and horizontal scanout position vpos, hpos,
		 * and bounding timestamps stime, etime, pre/post query.
		 */
703
		vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
704
							       &hpos, &stime, &etime);
705 706 707 708 709 710 711 712

		/* Return as no-op if scanout query unsupported or failed. */
		if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
			DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
				  crtc, vbl_status);
			return -EIO;
		}

713
		/* Compute uncertainty in timestamp of scanout position query. */
714
		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
715 716

		/* Accept result with <  max_error nsecs timing uncertainty. */
717
		if (duration_ns <= *max_error)
718 719 720 721 722 723
			break;
	}

	/* Noisy system timing? */
	if (i == DRM_TIMESTAMP_MAXRETRIES) {
		DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
724
			  crtc, duration_ns/1000, *max_error/1000, i);
725 726 727
	}

	/* Return upper bound of timestamp precision error. */
728
	*max_error = duration_ns;
729 730 731 732 733 734

	/* Check if in vblank area:
	 * vpos is >=0 in video scanout area, but negative
	 * within vblank area, counting down the number of lines until
	 * start of scanout.
	 */
735
	invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
736 737 738 739 740

	/* Convert scanout position into elapsed time at raw_time query
	 * since start of scanout at first display scanline. delta_ns
	 * can be negative if start of scanout hasn't happened yet.
	 */
741
	delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
742

743
	if (!drm_timestamp_monotonic)
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		etime = ktime_mono_to_real(etime);
745

746 747
	/* save this only for debugging purposes */
	tv_etime = ktime_to_timeval(etime);
748 749 750
	/* Subtract time delta from raw timestamp to get final
	 * vblank_time timestamp for end of vblank.
	 */
751 752 753 754
	if (delta_ns < 0)
		etime = ktime_add_ns(etime, -delta_ns);
	else
		etime = ktime_sub_ns(etime, delta_ns);
755
	*vblank_time = ktime_to_timeval(etime);
756

757 758
	DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
		  crtc, (int)vbl_status, hpos, vpos,
759
		  (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
760
		  (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
761
		  duration_ns/1000, i);
762 763 764

	vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
	if (invbl)
765
		vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
766 767 768 769 770

	return vbl_status;
}
EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);

771 772 773 774
static struct timeval get_drm_timestamp(void)
{
	ktime_t now;

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	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
776 777 778
	return ktime_to_timeval(now);
}

779 780
/**
 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
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 * 			       vblank interval
782
 * @dev: DRM device
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 * @crtc: which CRTC's vblank timestamp to retrieve
784 785
 * @tvblank: Pointer to target struct timeval which should receive the timestamp
 * @flags: Flags to pass to driver:
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 *         0 = Default,
 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
788 789
 *
 * Fetches the system timestamp corresponding to the time of the most recent
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 * vblank interval on specified CRTC. May call into kms-driver to
791 792 793 794 795
 * compute the timestamp with a high-precision GPU specific method.
 *
 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
 * call, i.e., it isn't very precisely locked to the true vblank.
 *
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 * Returns:
797
 * True if timestamp is considered to be very precise, false otherwise.
798
 */
799 800 801
static bool
drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
			  struct timeval *tvblank, unsigned flags)
802
{
803
	int ret;
804 805 806 807 808 809 810 811 812

	/* Define requested maximum error on timestamps (nanoseconds). */
	int max_error = (int) drm_timestamp_precision * 1000;

	/* Query driver if possible and precision timestamping enabled. */
	if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
		ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
							tvblank, flags);
		if (ret > 0)
813
			return true;
814 815 816
	}

	/* GPU high precision timestamp query unsupported or failed.
817
	 * Return current monotonic/gettimeofday timestamp as best estimate.
818
	 */
819
	*tvblank = get_drm_timestamp();
820

821
	return false;
822 823
}

824 825 826 827 828 829 830 831
/**
 * drm_vblank_count - retrieve "cooked" vblank counter value
 * @dev: DRM device
 * @crtc: which counter to retrieve
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity.
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 *
 * Returns:
 * The software vblank counter.
835 836 837
 */
u32 drm_vblank_count(struct drm_device *dev, int crtc)
{
838 839
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

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	if (WARN_ON(crtc >= dev->num_crtcs))
		return 0;
842
	return atomic_read(&vblank->count);
843 844 845
}
EXPORT_SYMBOL(drm_vblank_count);

846 847 848 849 850 851 852 853 854 855 856
/**
 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
 * and the system timestamp corresponding to that vblank counter value.
 *
 * @dev: DRM device
 * @crtc: which counter to retrieve
 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity. Returns corresponding system timestamp of the time
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 * of the vblank interval that corresponds to the current vblank counter value.
858 859 860 861
 */
u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
			      struct timeval *vblanktime)
{
862
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
863 864
	u32 cur_vblank;

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	if (WARN_ON(crtc >= dev->num_crtcs))
		return 0;

868 869 870 871 872 873
	/* Read timestamp from slot of _vblank_time ringbuffer
	 * that corresponds to current vblank count. Retry if
	 * count has incremented during readout. This works like
	 * a seqlock.
	 */
	do {
874
		cur_vblank = atomic_read(&vblank->count);
875 876
		*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
		smp_rmb();
877
	} while (cur_vblank != atomic_read(&vblank->count));
878 879 880 881 882

	return cur_vblank;
}
EXPORT_SYMBOL(drm_vblank_count_and_time);

883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906
static void send_vblank_event(struct drm_device *dev,
		struct drm_pending_vblank_event *e,
		unsigned long seq, struct timeval *now)
{
	WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
	e->event.sequence = seq;
	e->event.tv_sec = now->tv_sec;
	e->event.tv_usec = now->tv_usec;

	list_add_tail(&e->base.link,
		      &e->base.file_priv->event_list);
	wake_up_interruptible(&e->base.file_priv->event_wait);
	trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
					 e->event.sequence);
}

/**
 * drm_send_vblank_event - helper to send vblank event after pageflip
 * @dev: DRM device
 * @crtc: CRTC in question
 * @e: the event to send
 *
 * Updates sequence # and timestamp on event, and sends it to userspace.
 * Caller must hold event lock.
907 908
 *
 * This is the legacy version of drm_crtc_send_vblank_event().
909 910 911 912 913 914 915 916 917 918
 */
void drm_send_vblank_event(struct drm_device *dev, int crtc,
		struct drm_pending_vblank_event *e)
{
	struct timeval now;
	unsigned int seq;
	if (crtc >= 0) {
		seq = drm_vblank_count_and_time(dev, crtc, &now);
	} else {
		seq = 0;
919 920

		now = get_drm_timestamp();
921
	}
922
	e->pipe = crtc;
923 924 925 926
	send_vblank_event(dev, e, seq, &now);
}
EXPORT_SYMBOL(drm_send_vblank_event);

927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943
/**
 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
 * @crtc: the source CRTC of the vblank event
 * @e: the event to send
 *
 * Updates sequence # and timestamp on event, and sends it to userspace.
 * Caller must hold event lock.
 *
 * This is the native KMS version of drm_send_vblank_event().
 */
void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
				struct drm_pending_vblank_event *e)
{
	drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
}
EXPORT_SYMBOL(drm_crtc_send_vblank_event);

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/**
 * drm_vblank_enable - enable the vblank interrupt on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
 */
static int drm_vblank_enable(struct drm_device *dev, int crtc)
{
951
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	int ret = 0;

	assert_spin_locked(&dev->vbl_lock);

	spin_lock(&dev->vblank_time_lock);

958
	if (!vblank->enabled) {
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		/*
		 * Enable vblank irqs under vblank_time_lock protection.
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		 * All vblank count & timestamp updates are held off
		 * until we are done reinitializing master counter and
		 * timestamps. Filtercode in drm_handle_vblank() will
		 * prevent double-accounting of same vblank interval.
		 */
		ret = dev->driver->enable_vblank(dev, crtc);
		DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
		if (ret)
969
			atomic_dec(&vblank->refcount);
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Ville Syrjälä 已提交
970
		else {
971
			vblank->enabled = true;
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			drm_update_vblank_count(dev, crtc);
		}
	}

	spin_unlock(&dev->vblank_time_lock);

	return ret;
}

981 982 983 984 985 986 987 988
/**
 * drm_vblank_get - get a reference count on vblank events
 * @dev: DRM device
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
989 990
 * This is the legacy version of drm_crtc_vblank_get().
 *
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 * Returns:
992 993 994 995
 * Zero on success, nonzero on failure.
 */
int drm_vblank_get(struct drm_device *dev, int crtc)
{
996
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
997
	unsigned long irqflags;
998 999
	int ret = 0;

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	if (WARN_ON(crtc >= dev->num_crtcs))
		return -EINVAL;

1003 1004
	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	/* Going from 0->1 means we have to enable interrupts again */
1005
	if (atomic_add_return(1, &vblank->refcount) == 1) {
V
Ville Syrjälä 已提交
1006
		ret = drm_vblank_enable(dev, crtc);
1007
	} else {
1008 1009
		if (!vblank->enabled) {
			atomic_dec(&vblank->refcount);
1010
			ret = -EINVAL;
1011 1012 1013 1014 1015 1016 1017 1018
		}
	}
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

	return ret;
}
EXPORT_SYMBOL(drm_vblank_get);

1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036
/**
 * drm_crtc_vblank_get - get a reference count on vblank events
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
 * This is the native kms version of drm_vblank_off().
 *
 * Returns:
 * Zero on success, nonzero on failure.
 */
int drm_crtc_vblank_get(struct drm_crtc *crtc)
{
	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_get);

1037 1038 1039 1040 1041 1042
/**
 * drm_vblank_put - give up ownership of vblank events
 * @dev: DRM device
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
1043
 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1044 1045
 *
 * This is the legacy version of drm_crtc_vblank_put().
1046 1047 1048
 */
void drm_vblank_put(struct drm_device *dev, int crtc)
{
1049 1050
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

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1051 1052
	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
		return;
1053

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	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

1057
	/* Last user schedules interrupt disable */
1058
	if (atomic_dec_and_test(&vblank->refcount)) {
1059 1060 1061
		if (drm_vblank_offdelay == 0)
			return;
		else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
1062
			vblank_disable_fn((unsigned long)vblank);
1063
		else
1064 1065 1066
			mod_timer(&vblank->disable_timer,
				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
	}
1067 1068 1069
}
EXPORT_SYMBOL(drm_vblank_put);

1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084
/**
 * drm_crtc_vblank_put - give up ownership of vblank events
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
 *
 * This is the native kms version of drm_vblank_put().
 */
void drm_crtc_vblank_put(struct drm_crtc *crtc)
{
	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_put);

1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
/**
 * drm_wait_one_vblank - wait for one vblank
 * @dev: DRM device
 * @crtc: crtc index
 *
 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
 * due to lack of driver support or because the crtc is off.
 */
void drm_wait_one_vblank(struct drm_device *dev, int crtc)
{
	int ret;
	u32 last;

	ret = drm_vblank_get(dev, crtc);
1100
	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
1101 1102 1103 1104 1105 1106 1107 1108
		return;

	last = drm_vblank_count(dev, crtc);

	ret = wait_event_timeout(dev->vblank[crtc].queue,
				 last != drm_vblank_count(dev, crtc),
				 msecs_to_jiffies(100));

1109
	WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128

	drm_vblank_put(dev, crtc);
}
EXPORT_SYMBOL(drm_wait_one_vblank);

/**
 * drm_crtc_wait_one_vblank - wait for one vblank
 * @crtc: DRM crtc
 *
 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
 * due to lack of driver support or because the crtc is off.
 */
void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
{
	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_wait_one_vblank);

1129 1130 1131 1132 1133
/**
 * drm_vblank_off - disable vblank events on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
 *
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 * Drivers can use this function to shut down the vblank interrupt handling when
 * disabling a crtc. This function ensures that the latest vblank frame count is
 * stored so that drm_vblank_on() can restore it again.
 *
 * Drivers must use this function when the hardware vblank counter can get
 * reset, e.g. when suspending.
1140 1141
 *
 * This is the legacy version of drm_crtc_vblank_off().
1142
 */
1143 1144
void drm_vblank_off(struct drm_device *dev, int crtc)
{
1145
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1146 1147
	struct drm_pending_vblank_event *e, *t;
	struct timeval now;
1148
	unsigned long irqflags;
1149
	unsigned int seq;
1150

R
Rob Clark 已提交
1151 1152 1153
	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

1154 1155 1156
	spin_lock_irqsave(&dev->event_lock, irqflags);

	spin_lock(&dev->vbl_lock);
1157
	vblank_disable_and_save(dev, crtc);
1158
	wake_up(&vblank->queue);
1159

1160 1161 1162 1163 1164 1165 1166 1167 1168 1169
	/*
	 * Prevent subsequent drm_vblank_get() from re-enabling
	 * the vblank interrupt by bumping the refcount.
	 */
	if (!vblank->inmodeset) {
		atomic_inc(&vblank->refcount);
		vblank->inmodeset = 1;
	}
	spin_unlock(&dev->vbl_lock);

1170 1171
	/* Send any queued vblank events, lest the natives grow disquiet */
	seq = drm_vblank_count_and_time(dev, crtc, &now);
1172

1173 1174 1175 1176 1177 1178
	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
		if (e->pipe != crtc)
			continue;
		DRM_DEBUG("Sending premature vblank event on disable: \
			  wanted %d, current %d\n",
			  e->event.sequence, seq);
1179
		list_del(&e->base.link);
1180
		drm_vblank_put(dev, e->pipe);
1181
		send_vblank_event(dev, e, seq, &now);
1182
	}
1183
	spin_unlock_irqrestore(&dev->event_lock, irqflags);
1184 1185 1186
}
EXPORT_SYMBOL(drm_vblank_off);

1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205
/**
 * drm_crtc_vblank_off - disable vblank events on a CRTC
 * @crtc: CRTC in question
 *
 * Drivers can use this function to shut down the vblank interrupt handling when
 * disabling a crtc. This function ensures that the latest vblank frame count is
 * stored so that drm_vblank_on can restore it again.
 *
 * Drivers must use this function when the hardware vblank counter can get
 * reset, e.g. when suspending.
 *
 * This is the native kms version of drm_vblank_off().
 */
void drm_crtc_vblank_off(struct drm_crtc *crtc)
{
	drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_off);

V
Ville Syrjälä 已提交
1206 1207 1208 1209
/**
 * drm_vblank_on - enable vblank events on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
D
Daniel Vetter 已提交
1210 1211 1212
 *
 * This functions restores the vblank interrupt state captured with
 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1213
 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
D
Daniel Vetter 已提交
1214
 * in driver load code to reflect the current hardware state of the crtc.
1215 1216
 *
 * This is the legacy version of drm_crtc_vblank_on().
V
Ville Syrjälä 已提交
1217 1218 1219
 */
void drm_vblank_on(struct drm_device *dev, int crtc)
{
1220
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
V
Ville Syrjälä 已提交
1221 1222
	unsigned long irqflags;

R
Rob Clark 已提交
1223 1224 1225
	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

V
Ville Syrjälä 已提交
1226
	spin_lock_irqsave(&dev->vbl_lock, irqflags);
1227
	/* Drop our private "prevent drm_vblank_get" refcount */
1228 1229 1230
	if (vblank->inmodeset) {
		atomic_dec(&vblank->refcount);
		vblank->inmodeset = 0;
1231
	}
1232 1233 1234 1235 1236 1237 1238 1239

	/*
	 * sample the current counter to avoid random jumps
	 * when drm_vblank_enable() applies the diff
	 *
	 * -1 to make sure user will never see the same
	 * vblank counter value before and after a modeset
	 */
1240
	vblank->last =
1241 1242
		(dev->driver->get_vblank_counter(dev, crtc) - 1) &
		dev->max_vblank_count;
1243 1244 1245 1246 1247 1248
	/*
	 * re-enable interrupts if there are users left, or the
	 * user wishes vblank interrupts to be enabled all the time.
	 */
	if (atomic_read(&vblank->refcount) != 0 ||
	    (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
V
Ville Syrjälä 已提交
1249 1250 1251 1252 1253
		WARN_ON(drm_vblank_enable(dev, crtc));
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
EXPORT_SYMBOL(drm_vblank_on);

1254 1255 1256 1257 1258 1259
/**
 * drm_crtc_vblank_on - enable vblank events on a CRTC
 * @crtc: CRTC in question
 *
 * This functions restores the vblank interrupt state captured with
 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1260
 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270
 * in driver load code to reflect the current hardware state of the crtc.
 *
 * This is the native kms version of drm_vblank_on().
 */
void drm_crtc_vblank_on(struct drm_crtc *crtc)
{
	drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_on);

D
Dave Airlie 已提交
1271 1272 1273 1274 1275 1276 1277
/**
 * drm_vblank_pre_modeset - account for vblanks across mode sets
 * @dev: DRM device
 * @crtc: CRTC in question
 *
 * Account for vblank events across mode setting events, which will likely
 * reset the hardware frame counter.
D
Daniel Vetter 已提交
1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
 *
 * This is done by grabbing a temporary vblank reference to ensure that the
 * vblank interrupt keeps running across the modeset sequence. With this the
 * software-side vblank frame counting will ensure that there are no jumps or
 * discontinuities.
 *
 * Unfortunately this approach is racy and also doesn't work when the vblank
 * interrupt stops running, e.g. across system suspend resume. It is therefore
 * highly recommended that drivers use the newer drm_vblank_off() and
 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
 * using "cooked" software vblank frame counters and not relying on any hardware
 * counters.
 *
 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
 * again.
D
Dave Airlie 已提交
1293 1294 1295
 */
void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
{
1296 1297
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

1298
	/* vblank is not initialized (IRQ not installed ?), or has been freed */
1299 1300
	if (!dev->num_crtcs)
		return;
R
Rob Clark 已提交
1301 1302 1303 1304

	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

D
Dave Airlie 已提交
1305 1306 1307 1308 1309 1310 1311
	/*
	 * To avoid all the problems that might happen if interrupts
	 * were enabled/disabled around or between these calls, we just
	 * have the kernel take a reference on the CRTC (just once though
	 * to avoid corrupting the count if multiple, mismatch calls occur),
	 * so that interrupts remain enabled in the interim.
	 */
1312 1313
	if (!vblank->inmodeset) {
		vblank->inmodeset = 0x1;
1314
		if (drm_vblank_get(dev, crtc) == 0)
1315
			vblank->inmodeset |= 0x2;
D
Dave Airlie 已提交
1316 1317 1318 1319
	}
}
EXPORT_SYMBOL(drm_vblank_pre_modeset);

D
Daniel Vetter 已提交
1320 1321 1322 1323 1324 1325 1326 1327
/**
 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
 * @dev: DRM device
 * @crtc: CRTC in question
 *
 * This function again drops the temporary vblank reference acquired in
 * drm_vblank_pre_modeset.
 */
D
Dave Airlie 已提交
1328 1329
void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
{
1330
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
D
Dave Airlie 已提交
1331 1332
	unsigned long irqflags;

1333 1334 1335 1336
	/* vblank is not initialized (IRQ not installed ?), or has been freed */
	if (!dev->num_crtcs)
		return;

1337
	if (vblank->inmodeset) {
D
Dave Airlie 已提交
1338
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
1339
		dev->vblank_disable_allowed = true;
D
Dave Airlie 已提交
1340
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1341

1342
		if (vblank->inmodeset & 0x2)
1343 1344
			drm_vblank_put(dev, crtc);

1345
		vblank->inmodeset = 0;
D
Dave Airlie 已提交
1346 1347 1348 1349
	}
}
EXPORT_SYMBOL(drm_vblank_post_modeset);

D
Daniel Vetter 已提交
1350
/*
1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364
 * drm_modeset_ctl - handle vblank event counter changes across mode switch
 * @DRM_IOCTL_ARGS: standard ioctl arguments
 *
 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 * ioctls around modesetting so that any lost vblank events are accounted for.
 *
 * Generally the counter will reset across mode sets.  If interrupts are
 * enabled around this call, we don't have to do anything since the counter
 * will have already been incremented.
 */
int drm_modeset_ctl(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_modeset_ctl *modeset = data;
1365
	unsigned int crtc;
1366 1367 1368

	/* If drm_vblank_init() hasn't been called yet, just no-op */
	if (!dev->num_crtcs)
1369
		return 0;
1370

1371 1372 1373 1374
	/* KMS drivers handle this internally */
	if (drm_core_check_feature(dev, DRIVER_MODESET))
		return 0;

1375
	crtc = modeset->crtc;
1376 1377
	if (crtc >= dev->num_crtcs)
		return -EINVAL;
1378 1379 1380

	switch (modeset->cmd) {
	case _DRM_PRE_MODESET:
D
Dave Airlie 已提交
1381
		drm_vblank_pre_modeset(dev, crtc);
1382 1383
		break;
	case _DRM_POST_MODESET:
D
Dave Airlie 已提交
1384
		drm_vblank_post_modeset(dev, crtc);
1385 1386
		break;
	default:
1387
		return -EINVAL;
1388 1389
	}

1390
	return 0;
1391 1392
}

1393 1394 1395 1396
static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
				  union drm_wait_vblank *vblwait,
				  struct drm_file *file_priv)
{
1397
	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1398 1399 1400 1401
	struct drm_pending_vblank_event *e;
	struct timeval now;
	unsigned long flags;
	unsigned int seq;
1402
	int ret;
1403 1404

	e = kzalloc(sizeof *e, GFP_KERNEL);
1405 1406 1407 1408
	if (e == NULL) {
		ret = -ENOMEM;
		goto err_put;
	}
1409 1410

	e->pipe = pipe;
1411
	e->base.pid = current->pid;
1412 1413 1414 1415 1416 1417 1418 1419 1420
	e->event.base.type = DRM_EVENT_VBLANK;
	e->event.base.length = sizeof e->event;
	e->event.user_data = vblwait->request.signal;
	e->base.event = &e->event.base;
	e->base.file_priv = file_priv;
	e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;

	spin_lock_irqsave(&dev->event_lock, flags);

1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432
	/*
	 * drm_vblank_off() might have been called after we called
	 * drm_vblank_get(). drm_vblank_off() holds event_lock
	 * around the vblank disable, so no need for further locking.
	 * The reference from drm_vblank_get() protects against
	 * vblank disable from another source.
	 */
	if (!vblank->enabled) {
		ret = -EINVAL;
		goto err_unlock;
	}

1433
	if (file_priv->event_space < sizeof e->event) {
1434 1435
		ret = -EBUSY;
		goto err_unlock;
1436 1437 1438
	}

	file_priv->event_space -= sizeof e->event;
1439 1440
	seq = drm_vblank_count_and_time(dev, pipe, &now);

1441 1442 1443
	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
	    (seq - vblwait->request.sequence) <= (1 << 23)) {
		vblwait->request.sequence = seq + 1;
1444
		vblwait->reply.sequence = vblwait->request.sequence;
1445 1446 1447 1448 1449
	}

	DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
		  vblwait->request.sequence, seq, pipe);

1450 1451 1452
	trace_drm_vblank_event_queued(current->pid, pipe,
				      vblwait->request.sequence);

1453 1454
	e->event.sequence = vblwait->request.sequence;
	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1455
		drm_vblank_put(dev, pipe);
1456
		send_vblank_event(dev, e, seq, &now);
1457
		vblwait->reply.sequence = seq;
1458
	} else {
1459
		/* drm_handle_vblank_events will call drm_vblank_put */
1460
		list_add_tail(&e->base.link, &dev->vblank_event_list);
1461
		vblwait->reply.sequence = vblwait->request.sequence;
1462 1463 1464 1465 1466
	}

	spin_unlock_irqrestore(&dev->event_lock, flags);

	return 0;
1467 1468 1469 1470 1471

err_unlock:
	spin_unlock_irqrestore(&dev->event_lock, flags);
	kfree(e);
err_put:
1472
	drm_vblank_put(dev, pipe);
1473
	return ret;
1474 1475
}

D
Daniel Vetter 已提交
1476
/*
L
Linus Torvalds 已提交
1477 1478 1479
 * Wait for VBLANK.
 *
 * \param inode device inode.
1480
 * \param file_priv DRM file private.
L
Linus Torvalds 已提交
1481 1482 1483 1484
 * \param cmd command.
 * \param data user argument, pointing to a drm_wait_vblank structure.
 * \return zero on success or a negative number on failure.
 *
1485 1486
 * This function enables the vblank interrupt on the pipe requested, then
 * sleeps waiting for the requested sequence number to occur, and drops
D
Daniel Vetter 已提交
1487
 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1488
 * after a timeout with no further vblank waits scheduled).
L
Linus Torvalds 已提交
1489
 */
1490 1491
int drm_wait_vblank(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
L
Linus Torvalds 已提交
1492
{
1493
	struct drm_vblank_crtc *vblank;
1494
	union drm_wait_vblank *vblwait = data;
1495
	int ret;
1496
	unsigned int flags, seq, crtc, high_crtc;
L
Linus Torvalds 已提交
1497

1498 1499
	if (!dev->irq_enabled)
		return -EINVAL;
L
Linus Torvalds 已提交
1500

1501 1502 1503
	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
		return -EINVAL;

1504
	if (vblwait->request.type &
1505 1506
	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
1507
		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1508
			  vblwait->request.type,
1509 1510
			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
			   _DRM_VBLANK_HIGH_CRTC_MASK));
1511 1512 1513
		return -EINVAL;
	}

1514
	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1515 1516 1517 1518 1519
	high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
	if (high_crtc)
		crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
	else
		crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1520
	if (crtc >= dev->num_crtcs)
1521 1522
		return -EINVAL;

1523 1524
	vblank = &dev->vblank[crtc];

1525 1526
	ret = drm_vblank_get(dev, crtc);
	if (ret) {
1527
		DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1528 1529 1530
		return ret;
	}
	seq = drm_vblank_count(dev, crtc);
1531

1532
	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
L
Linus Torvalds 已提交
1533
	case _DRM_VBLANK_RELATIVE:
1534 1535
		vblwait->request.sequence += seq;
		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
L
Linus Torvalds 已提交
1536 1537 1538
	case _DRM_VBLANK_ABSOLUTE:
		break;
	default:
1539 1540
		ret = -EINVAL;
		goto done;
L
Linus Torvalds 已提交
1541 1542
	}

1543 1544 1545 1546
	if (flags & _DRM_VBLANK_EVENT) {
		/* must hold on to the vblank ref until the event fires
		 * drm_vblank_put will be called asynchronously
		 */
1547
		return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1548
	}
1549

1550
	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1551 1552
	    (seq - vblwait->request.sequence) <= (1<<23)) {
		vblwait->request.sequence = seq + 1;
1553 1554
	}

1555 1556
	DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
		  vblwait->request.sequence, crtc);
1557 1558
	vblank->last_wait = vblwait->request.sequence;
	DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1559 1560
		    (((drm_vblank_count(dev, crtc) -
		       vblwait->request.sequence) <= (1 << 23)) ||
1561
		     !vblank->enabled ||
1562
		     !dev->irq_enabled));
L
Linus Torvalds 已提交
1563

1564 1565
	if (ret != -EINTR) {
		struct timeval now;
L
Linus Torvalds 已提交
1566

1567
		vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1568 1569
		vblwait->reply.tval_sec = now.tv_sec;
		vblwait->reply.tval_usec = now.tv_usec;
1570

1571 1572
		DRM_DEBUG("returning %d to client\n",
			  vblwait->reply.sequence);
L
Linus Torvalds 已提交
1573
	} else {
1574
		DRM_DEBUG("vblank wait interrupted by signal\n");
L
Linus Torvalds 已提交
1575 1576
	}

1577 1578
done:
	drm_vblank_put(dev, crtc);
L
Linus Torvalds 已提交
1579 1580 1581
	return ret;
}

1582
static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1583 1584 1585 1586 1587
{
	struct drm_pending_vblank_event *e, *t;
	struct timeval now;
	unsigned int seq;

1588
	assert_spin_locked(&dev->event_lock);
1589

1590
	seq = drm_vblank_count_and_time(dev, crtc, &now);
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600

	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
		if (e->pipe != crtc)
			continue;
		if ((seq - e->event.sequence) > (1<<23))
			continue;

		DRM_DEBUG("vblank event on %d, current %d\n",
			  e->event.sequence, seq);

1601
		list_del(&e->base.link);
1602
		drm_vblank_put(dev, e->pipe);
1603
		send_vblank_event(dev, e, seq, &now);
1604 1605
	}

J
Jesse Barnes 已提交
1606
	trace_drm_vblank_event(crtc, seq);
1607 1608
}

1609 1610 1611 1612 1613 1614 1615 1616
/**
 * drm_handle_vblank - handle a vblank event
 * @dev: DRM device
 * @crtc: where this event occurred
 *
 * Drivers should call this routine in their vblank interrupt handlers to
 * update the vblank counter and send any signals that may be pending.
 */
1617
bool drm_handle_vblank(struct drm_device *dev, int crtc)
1618
{
1619
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1620 1621 1622 1623 1624
	u32 vblcount;
	s64 diff_ns;
	struct timeval tvblank;
	unsigned long irqflags;

1625
	if (!dev->num_crtcs)
1626
		return false;
1627

R
Rob Clark 已提交
1628 1629 1630
	if (WARN_ON(crtc >= dev->num_crtcs))
		return false;

1631 1632
	spin_lock_irqsave(&dev->event_lock, irqflags);

1633 1634 1635 1636
	/* Need timestamp lock to prevent concurrent execution with
	 * vblank enable/disable, as this would cause inconsistent
	 * or corrupted timestamps and vblank counts.
	 */
1637
	spin_lock(&dev->vblank_time_lock);
1638 1639

	/* Vblank irq handling disabled. Nothing to do. */
1640
	if (!vblank->enabled) {
1641 1642
		spin_unlock(&dev->vblank_time_lock);
		spin_unlock_irqrestore(&dev->event_lock, irqflags);
1643
		return false;
1644 1645 1646 1647 1648 1649 1650
	}

	/* Fetch corresponding timestamp for this vblank interval from
	 * driver and store it in proper slot of timestamp ringbuffer.
	 */

	/* Get current timestamp and count. */
1651
	vblcount = atomic_read(&vblank->count);
1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666
	drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);

	/* Compute time difference to timestamp of last vblank */
	diff_ns = timeval_to_ns(&tvblank) -
		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));

	/* Update vblank timestamp and count if at least
	 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
	 * difference between last stored timestamp and current
	 * timestamp. A smaller difference means basically
	 * identical timestamps. Happens if this vblank has
	 * been already processed and this is a redundant call,
	 * e.g., due to spurious vblank interrupts. We need to
	 * ignore those for accounting.
	 */
1667
	if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1668 1669 1670 1671 1672 1673
		/* Store new timestamp in ringbuffer. */
		vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;

		/* Increment cooked vblank count. This also atomically commits
		 * the timestamp computed above.
		 */
1674
		smp_mb__before_atomic();
1675
		atomic_inc(&vblank->count);
1676
		smp_mb__after_atomic();
1677 1678 1679 1680 1681
	} else {
		DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
			  crtc, (int) diff_ns);
	}

1682 1683
	spin_unlock(&dev->vblank_time_lock);

1684
	wake_up(&vblank->queue);
1685
	drm_handle_vblank_events(dev, crtc);
1686

1687 1688
	spin_unlock_irqrestore(&dev->event_lock, irqflags);

1689
	return true;
1690 1691
}
EXPORT_SYMBOL(drm_handle_vblank);