The new function balances virtio_gpu_object_attach().

Also make virtio_gpu_cmd_resource_inval_backing() static and switch
call sites to the new virtio_gpu_object_attach() function.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NDave Airlie <airlied@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180829122026.27012-2-kraxel@redhat.com

Track whenever an virtual output (crtc) is enabled or disabled.

On atomic updates check for both framebuffer being present and crtc
being enabled to figure whenever the output is active or not.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NDave Airlie <airlied@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180813152855.12863-1-kraxel@redhat.com

"crtc->helper_private" is not initialized by the QXL driver and thus the
"crtc_funcs->disable" call would crash (resulting in suspend failure).
Fix this by converting the suspend/resume functions to use the
drm_mode_config_helper_* helpers.

Tested system sleep with QEMU 3.0 using "echo mem > /sys/power/state".
During suspend the following message is visible from QEMU:

    spice/server/display-channel.c:2425:display_channel_validate_surface: canvas address is 0x7fd05da68308 for 0 (and is NULL)
    spice/server/display-channel.c:2426:display_channel_validate_surface: failed on 0

This seems to be triggered by QXL_IO_NOTIFY_CMD after
QXL_IO_DESTROY_PRIMARY_ASYNC, but aside from the warning things still
seem to work (tested with both the GTK and -spice options).
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Link: http://patchwork.freedesktop.org/patch/msgid/20180904202747.14968-1-peter@lekensteyn.nlSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

Using a spinlock to serialize the destroy function, within the destroy
function itself does not prevent the buggy driver from shooting
themselves in the foot - either way they still have a use-after-free
issue.
Reported-by: NJia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180903093155.3825-1-chris@chris-wilson.co.uk

The ioctl arguments are under control of the user and as such we should
resist any temptation to flood the kernel logs with their errors.
Relegate the DRM_ERROR to a DRM_DEBUG so the user has to opt into
hearing of their own mistakes. (One day we will have a small ringbuffer
attached to the task, so that the concerned process can inspect its own
debug info for EINVAL without them being hitting syslog at all.)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180904115719.24525-1-chris@chris-wilson.co.uk

We have introduce new return type vm_fault_t for
fault handler. Update the document for the same.
Signed-off-by: NSouptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180904041505.GA2712@jordon-HP-15-Notebook-PC

Kick out firmware fb when loading Tegra driver.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/b5c3972e5774d0d1f8887054a993bbc54e9dbe2a.1535810304.git.mirq-linux@rere.qmqm.pl

Use remove_conflicting_framebuffers(NULL) instead of duplicating it.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/7d6d5bc4deac322b1351533c989cb3583e91be49.1535810304.git.mirq-linux@rere.qmqm.pl

Use remove_conflicting_framebuffers(NULL) instead of open-coding it.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NEric Anholt <eric@anholt.net>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/be7e6396e6e7159695a5bccc109c6ab49a51e0d8.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/25f89daf6217da98a52d41c4ad62a78272bb0cf6.1535810304.git.mirq-linux@rere.qmqm.pl

Remove duplicated call, while at it.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/90fc954f90de44157d6cc1c782147db6252c71e4.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/b61a2e458b6a2964039693d724cc75b4fcfb3ddb.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/b5fce8eba7472e5ba8e18c2624938be6c5aa6ebb.1535810304.git.mirq-linux@rere.qmqm.pl
Link: https://patchwork.freedesktop.org/patch/msgid/a9a4691b6eea789664edd6b85a85b7990953a222.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/a9a4691b6eea789664edd6b85a85b7990953a222.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/fe59ab587ef4ef799b525fcc03d87800c5dc26d9.1535810304.git.mirq-linux@rere.qmqm.pl

Almost all PCI drivers using remove_conflicting_framebuffers() wrap it
with the same code.

v2: add kerneldoc for DRM helper
v3: propagate remove_conflicting_framebuffers() return value
  + move kerneldoc to where function is implemented
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/7db1c278276de420eb45a1b71d06b5eb6bbd49ef.1535810304.git.mirq-linux@rere.qmqm.pl

Document remove_conflicting_framebuffers() behaviour.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/283fef19815b991700b56119d8d5874a2a8da44e.1535810304.git.mirq-linux@rere.qmqm.pl

Interpret (otherwise-invalid) NULL apertures argument to mean all-memory
range. This will allow to remove several duplicates of this code
from drivers in following patches.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/b5fed539fe569035139c8594c23effd8c39f12ca.1535810304.git.mirq-linux@rere.qmqm.pl

Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/ef584ecd8642e8b1a04f28d6d9c1864b5aa507bb.1535810304.git.mirq-linux@rere.qmqm.pl

A driver to let userspace turn memfd regions into dma-bufs.

Use case:  Allows qemu create dmabufs for the vga framebuffer or
virtio-gpu ressources.  Then they can be passed around to display
those guest things on the host.  To spice client for classic full
framebuffer display, and hopefully some day to wayland server for
seamless guest window display.

qemu test branch:
  https://git.kraxel.org/cgit/qemu/log/?h=sirius/udmabuf

Cc: David Airlie <airlied@linux.ie>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180827093444.23623-1-kraxel@redhat.com

Adds docs for pixel_blend_mode in drm_plane_state. Fixes the warning
found by kbuild test robot:

htmldocs: include/drm/drm_plane.h:189: warning: Function parameter or member 'pixel_blend_mode' not described in 'drm_plane_state'

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lowry Li <lowry.li@arm.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180831150934.202332-1-sean@poorly.run

Add DisplayPort CEC-Tunneling-over-AUX support to amdgpu.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/de9586bb-151e-bae9-b8e3-14db107a60df@xs4all.nl

Add DisplayPort CEC-Tunneling-over-AUX support to nouveau.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5c0b907d-0bf2-7b80-b4b6-cbde78b03f0d@xs4all.nl

When parsing the reply of a DP_REMOTE_DPCD_READ DPCD command the
result is wrong due to a missing idx increment.

This was never noticed since DP_REMOTE_DPCD_READ is currently not
used, but if you enable it, then it is all wrong.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e72ddac2-1dc0-100a-d816-9ac98ac009dd@xs4all.nl

A big problem with DP CEC-Tunneling-over-AUX is that it is tricky
to find adapters with a chipset that supports this AND where the
manufacturer actually connected the HDMI CEC line to the chipset.

Add a mention of the MegaChips 2900 chipset which seems to support
this feature well.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180827075820.41109-3-hverkuil@xs4all.nl

If aux->transfer == NULL, then just return without doing
anything. In that case the function is likely called for
a non-(e)DP connector.

This never happened for the i915 driver, but the nouveau and amdgpu
drivers need this check.

The alternative would be to add this check in those drivers before
every drm_dp_cec call, but it makes sense to check it in the
drm_dp_cec functions to prevent a kernel oops.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180827075820.41109-2-hverkuil@xs4all.nl

This doesn't affect runtime because in the current code "idx" is always
valid.

First, we read from "vgdev->capsets[idx].max_size" before checking
whether "idx" is within bounds.  And secondly the bounds check is off by
one so we could end up reading one element beyond the end of the
vgdev->capsets[] array.

Fixes: 62fb7a5e ("virtio-gpu: add 3d/virgl support")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180704094250.m7sgvvzg3dhcvv3h@kili.mountainSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

The function ttm_bo_put releases a reference to a TTM buffer object. The
function's name is more aligned to the Linux kernel convention of naming
ref-counting function _get and _put.

A call to ttm_bo_unref takes the address of the TTM BO object's pointer and
clears the pointer's value to NULL. This is not necessary in most cases and
sometimes even worked around by the calling code. A call to ttm_bo_put only
releases the reference without clearing the pointer.

The current behaviour of cleaning the pointer is kept in the calling code,
but should be removed if not required in a later patch.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20180731062127.10131-3-tzimmermann@suse.deSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

The function ttm_bo_get acquires a reference on a TTM buffer object. The
function's name is more aligned to the Linux kernel convention of naming
ref-counting function _get and _put.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20180731062127.10131-2-tzimmermann@suse.deSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

The function ttm_bo_put releases a reference to a TTM buffer object. The
function's name is more aligned to the Linux kernel convention of naming
ref-counting function _get and _put.

A call to ttm_bo_unref takes the address of the TTM BO object's pointer and
clears the pointer's value to NULL. This is not necessary in most cases and
sometimes even worked around by the calling code. A call to ttm_bo_put only
releases the reference without clearing the pointer.

The current behaviour of cleaning the pointer is kept in the calling code,
but should be removed if not required in a later patch.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20180731063559.11629-1-tzimmermann@suse.deSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

The function ttm_bo_put releases a reference to a TTM buffer object. The
function's name is more aligned to the Linux kernel convention of naming
ref-counting function _get and _put.

A call to ttm_bo_unref takes the address of the TTM BO object's pointer and
clears the pointer's value to NULL. This is not necessary in most cases and
sometimes even worked around by the calling code. A call to ttm_bo_put only
releases the reference without clearing the pointer.

The current behaviour of cleaning the pointer is kept in the calling code,
but should be removed if not required in a later patch.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20180731063128.11041-1-tzimmermann@suse.deSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

The function ttm_bo_put releases a reference to a TTM buffer object. The
function's name is more aligned to the Linux kernel convention of naming
ref-counting function _get and _put.

A call to ttm_bo_unref takes the address of the TTM BO object's pointer and
clears the pointer's value to NULL. This is not necessary in most cases and
sometimes even worked around by the calling code. A call to ttm_bo_put only
releases the reference without clearing the pointer.

The current behaviour of cleaning the pointer is kept in the calling code,
but should be removed if not required in a later patch.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20180731062851.10812-1-tzimmermann@suse.deSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

1. interrupt register define error lead to enable interrupt failed;
2. px30 unsupport hdmi output;
3. there are some hardware designed bug, we must swap win2 gate and
   enable offset, otherwise will appear vop iommu pagefault.
Signed-off-by: NSandy Huang <hjc@rock-chips.com>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1535445150-40296-1-git-send-email-hjc@rock-chips.com

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
	int stuff;
        void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

or, like in this particular case:

size = sizeof(struct foo) + sizeof(void *) * count;
instance = devm_kzalloc(dev, size, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count),
GFP_KERNEL);

This issue was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180826184712.GA9330@embeddedor.com

Align with other drivers, tab + 2 space key for description.
and edp/hdmi/dsi can be used on both rk3288 and rk3399.
Signed-off-by: NSandy Huang <hjc@rock-chips.com>
Reviewed-by: NEnric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1535442295-4007-1-git-send-email-hjc@rock-chips.com

This beats the heuristic that the connector is involved in what format
should be output for cases where this fails.

E.g. if there is a bridge that changes format between the encoder and the
connector, or if some of the RGB pins between the lcd controller and the
encoder are not routed on the PCB.

This is critical for the devices that have the "conflicting output
formats" issue (SAM9N12, SAM9X5, SAMA5D3), since the most significant
RGB bits move around depending on the selected output mode. For
devices that do not have the "conflicting output formats" issue
(SAMA5D2, SAMA5D4), this is completely irrelevant.
Acked-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180825085620.10566-5-peda@axentia.se

This enables more flexible devicetrees. You can e.g. have two output
nodes where one is not enabled, without the ordering affecting things.

Prior to this patch the active nodes had to have endpoint id zero and
upwards consecutively.
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180825085620.10566-4-peda@axentia.se

With bus-type/bus-width properties in the endpoint nodes, the video-
interface of the connection can be specified for cases where the
heuristic fails to select the correct output mode. This can happen
e.g. if not all RGB pins are routed on the PCB; the driver has no
way of knowing this, and needs to be told explicitly.

This is critical for the devices that have the "conflicting output
formats" issue (SAM9N12, SAM9X5, SAMA5D3), since the most significant
RGB bits move around depending on the selected output mode. For
devices that do not have the "conflicting output formats" issue
(SAMA5D2, SAMA5D4), this is completely irrelevant.
Acked-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180825085620.10566-3-peda@axentia.se

Start list of actual chips compatible with "lvds-encoder".
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180825085620.10566-2-peda@axentia.se

But only if the highest pixel-clock frequency lower than requested
is significantly less accurate than the lowest frequency higher than
requested.

I pulled "10 times" as the discriminator out of the hat, and went with
that.

This is useful, if e.g. the target pixel-clock is 65MHz and the sys_clk
is 132MHz. In this case the highest possible pixel-clock lower than the
requested 65MHz is 52.8MHz, which is almost 20% off (and outside the
spec for the panel). The lowest possible pixel-clock higher than 65MHz
is 66MHz, which is a *much* better match, and only 1.5% off.
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180824092458.13165-3-peda@axentia.se