Rename various instances of pagelist to pagereflist. The list now
stores pageref structures, so the new name is more appropriate.

In their write-back helpers, several fbdev drivers refer to the
pageref list in struct fb_deferred_io instead of using the one
supplied as argument to the function. Convert them over to the
supplied one. It's the same instance, so no change of behavior
occurs.

v4:
	* fix commit message (Javier)
Suggested-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-5-tzimmermann@suse.de

Store the per-page state for fbdev's deferred I/O in struct
fb_deferred_io_pageref. Maintain a list of pagerefs for the pages
that have to be written back to video memory. Update all affected
drivers.

As with pages before, fbdev acquires a pageref when an mmaped page
of the framebuffer is being written to. It holds the pageref in a
list of all currently written pagerefs until it flushes the written
pages to video memory. Writeback occurs periodically. After writeback
fbdev releases all pagerefs and builds up a new dirty list until the
next writeback occurs.

Using pagerefs has a number of benefits.

For pages of the framebuffer, the deferred I/O code used struct
page.lru as an entry into the list of dirty pages. The lru field is
owned by the page cache, which makes deferred I/O incompatible with
some memory pages (e.g., most notably DRM's GEM SHMEM allocator).
struct fb_deferred_io_pageref now provides an entry into a list of
dirty framebuffer pages, freeing lru for use with the page cache.

Drivers also assumed that struct page.index is the page offset into
the framebuffer. This is not true for DRM buffers, which are located
at various offset within a mapped area. struct fb_deferred_io_pageref
explicitly stores an offset into the framebuffer. struct page.index
is now only the page offset into the mapped area.

These changes will allow DRM to use fbdev deferred I/O without an
intermediate shadow buffer.

v3:
	* use pageref->offset for sorting
	* fix grammar in comment
v2:
	* minor fixes in commit message
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-3-tzimmermann@suse.de

The fbdev mmap function fb_mmap() unconditionally overrides the
driver's implementation if deferred I/O has been activated. This
makes it hard to implement mmap with anything but a vmalloc()'ed
software buffer. That is specifically a problem for DRM, where
video memory is maintained by a memory manager.

Leave the mmap handling to drivers and expect them to call the
helper for deferred I/O by thmeselves.

v4:
	* unlock mm_lock in fb_mmap() error path (Dan)
v3:
	* fix warning if fb_mmap is missing (kernel test robot)
v2:
	* print a helpful error message if the defio setup is
	  incorrect (Javier)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-2-tzimmermann@suse.de

In certain situations it's useful to be able to write to an
offset of the mapping. Add a dst_offset to iosys_map_memcpy_to().

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220216174147.3073235-2-lucas.demarchi@intel.com

Clip the damage area horizontally if only a single scanline has been
changed. This is helpful to reduce the memcpy overhead for small writes.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-6-tzimmermann@suse.de

Write helpers used to mark the complete screen as dirty. This is
wasteful for writes that only change a small portion of the screen.
Fix the problem by computing the damaged area from the written
memory range and perform damage handling accordingly.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-5-tzimmermann@suse.de

Add drm_fb_helper_memory_range_to_clip(), a helper function that
accepts an linear range of video memory and converts it into a
rectangle. The computed rectangle describes the damaged area in
terms of scanlines and pixels per scanline.

While at it, make the code more readable by using struct drm_rect
and related helpers.

The code was previously part of the deferred I/O helpers, but is
also useful for damage handling of regular write operations. Update
the deferred I/O code to use the new function.

v2:
	* rename helper (Javier)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-4-tzimmermann@suse.de

Don't clip the damage rectangle against the viewport. This only
works if the viewport is located at the beginning of the video
memory and the video memory doesn't extend the screen (i.e., if
there's no overallocation).

Fbdev emulation transfers data from write operations into a
possible shadow buffer, then into a GEM buffer object, and finally
via graphics driver onto the screen.

If callers write outside the currently visible area, clipping the
damage rectangle against the viewport will loose these updates in
the shadow buffer and the fbdev's buffer object will contain stale
data. Panning the viewport to the stale area of the buffer will
display obsolete data.

Instead, mark all written areas as damaged, so that the damage
handler updates the buffer object from the shadow buffer for all
such areas. The graphics driver's later has the option of clipping
the damaged area against the viewport when updating the screen
from the buffer object.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-3-tzimmermann@suse.de

Computing the clip rectangle is prone to off-by-one errors when writes
happen near the end of a memory page. Point the end of the memory area
to the first trailing byte, so that (end - start) returns the area's
length.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-2-tzimmermann@suse.de

Rename struct dma_buf_map to struct iosys_map and corresponding APIs.
Over time dma-buf-map grew up to more functionality than the one used by
dma-buf: in fact it's just a shim layer to abstract system memory, that
can be accessed via regular load and store, from IO memory that needs to
be acessed via arch helpers.

The idea is to extend this API so it can fulfill other needs, internal
to a single driver. Example: in the i915 driver it's desired to share
the implementation for integrated graphics, which uses mostly system
memory, with discrete graphics, which may need to access IO memory.

The conversion was mostly done with the following semantic patch:

	@r1@
	@@
	- struct dma_buf_map
	+ struct iosys_map

	@r2@
	@@
	(
	- DMA_BUF_MAP_INIT_VADDR
	+ IOSYS_MAP_INIT_VADDR
	|
	- dma_buf_map_set_vaddr
	+ iosys_map_set_vaddr
	|
	- dma_buf_map_set_vaddr_iomem
	+ iosys_map_set_vaddr_iomem
	|
	- dma_buf_map_is_equal
	+ iosys_map_is_equal
	|
	- dma_buf_map_is_null
	+ iosys_map_is_null
	|
	- dma_buf_map_is_set
	+ iosys_map_is_set
	|
	- dma_buf_map_clear
	+ iosys_map_clear
	|
	- dma_buf_map_memcpy_to
	+ iosys_map_memcpy_to
	|
	- dma_buf_map_incr
	+ iosys_map_incr
	)

	@@
	@@
	- #include <linux/dma-buf-map.h>
	+ #include <linux/iosys-map.h>

Then some files had their includes adjusted and some comments were
update to remove mentions to dma-buf-map.

Since this is not specific to dma-buf anymore, move the documentation to
the "Bus-Independent Device Accesses" section.

v2:
  - Squash patches

v3:
  - Fix wrong removal of dma-buf.h from MAINTAINERS
  - Move documentation from dma-buf.rst to device-io.rst

v4:
  - Change documentation title and level
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: NChristian König <christian.koenig@amd.com>
Acked-by: NSumit Semwal <sumit.semwal@linaro.org>
Acked-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204170541.829227-1-lucas.demarchi@intel.com

Mark screen buffers in system memory with FBINFO_VIRTFB. Otherwise, fbdev
deferred I/O marks mmap'ed areas of system memory with VM_IO. (There's an
inverse relationship between the two flags.)

For shadow buffers, also set the FBINFO_READS_FAST hint.

v3:
	* change FB_ to FBINFO_ in commit description
v2:
	* updated commit description (Daniel)
	* added Fixes tag
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Fixes: d536540f ("drm/fb-helper: Add generic fbdev emulation .fb_probe function")
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.19+
Link: https://patchwork.freedesktop.org/patch/msgid/20220201115305.9333-1-tzimmermann@suse.de

This reverts commit b3484d2b.

That change attempted to improve the DRM drivers fbdev emulation device
names to avoid having confusing names like "simpledrmdrmfb" in /proc/fb.

But unfortunately, there are user-space programs such as pm-utils that
match against the fbdev names and so broke after the mentioned commit.

Since the names in /proc/fb are used by tools that consider it an uAPI,
let's restore the old names even when this lead to silly names like the
one mentioned above.

Fixes: b3484d2b ("drm/fb-helper: improve DRM fbdev emulation device names")
Reported-by: NJohannes Stezenbach <js@sig21.net>
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211020165740.3011927-1-javierm@redhat.com

Allocating a shadow buffer of the height of the buffer object does
not support fbdev overallocation. Use surface height instead.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211110103702.374-7-tzimmermann@suse.de

Clamp the fbdev surface size of the available maximumi height to avoid
failing to init console emulation. An example error is shown below.

  bad framebuffer height 2304, should be >= 768 && <= 768
  [drm] Initialized simpledrm 1.0.0 20200625 for simple-framebuffer.0 on minor 0
  simple-framebuffer simple-framebuffer.0: [drm] *ERROR* fbdev: Failed to setup generic emulation (ret=-22)

This is especially a problem with drivers that have very small screen
sizes and cannot over-allocate at all.

v2:
	* reduce warning level (Ville)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Fixes: 11e8f5fd ("drm: Add simpledrm driver")
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reported-by: NAmanoel Dawod <kernel@amanoeldawod.com>
Reported-by: NZoltán Kővágó <dirty.ice.hu@gmail.com>
Reported-by: NMichael Stapelberg <michael+lkml@stapelberg.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.14+
Link: https://patchwork.freedesktop.org/patch/msgid/20211005070355.7680-1-tzimmermann@suse.deSigned-off-by: NDave Airlie <airlied@redhat.com>

This reverts commit 7c5f2eec.

This patchset breaks on intel platforms and was previously NACK'd by
Ville.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fernando Ramos <greenfoo@u92.eu>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211002154542.15800-13-sean@poorly.run

As requested in Documentation/gpu/todo.rst, replace driver calls to
drm_modeset_lock_all() with DRM_MODESET_LOCK_ALL_BEGIN() and
DRM_MODESET_LOCK_ALL_END()
Signed-off-by: NFernando Ramos <greenfoo@u92.eu>
Reviewed-by: NSean Paul <sean@poorly.run>
Signed-off-by: NSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924064324.229457-5-greenfoo@u92.eu

fix typo for drm

v1->v2:
respin with the change "iff ==> implies that"
Signed-off-by: NCai Huoqing <caihuoqing@baidu.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730132729.376-1-caihuoqing@baidu.com

Framebuffer devices that are registered by DRM drivers for fbdev emulation
have a "drmfb" suffix in their name. But makes them to be quite confusing
for drivers that already have "drm" in their name:

$ cat /proc/fb
0 rockchipdrmdrmfb

$ cat /proc/fb
0 simpledrmdrmfb

Also, there isn't a lot of value in adding these "drmfb" suffices to their
names, since users shouldn't really care if the FB devices were registered
by a real fbdev driver or a DRM driver using the fbdev emulation.

What programs should be interested about is if there's a DRM device, and
there are better ways to query that info than reading this procfs entry.

So let's just remove the suffix, which leads to much better device names:

$ cat /proc/fb
0 rockchipdrm

$ cat /proc/fb
0 simpledrm
Suggested-by: NThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525151313.3379622-1-javierm@redhat.com

drm_fbdev_cleanup() can be called when fb_helper->buffer is null, hence
fb_helper->buffer should be checked before calling
drm_client_buffer_vunmap(). This buffer is also checked in
drm_client_framebuffer_delete(), so we should also do the same thing for
drm_client_buffer_vunmap().

[  199.128742] RIP: 0010:drm_client_buffer_vunmap+0xd/0x20
[  199.129031] Code: 43 18 48 8b 53 20 49 89 45 00 49 89 55 08 5b 44 89 e0 41 5c 41 5d 41 5e 5d
c3 0f 1f 00 53 48 89 fb 48 8d 7f 10 e8 73 7d a1 ff <48> 8b 7b 10 48 8d 73 18 5b e9 75 53 fc ff 0
f 1f 44 00 00 48 b8 00
[  199.130041] RSP: 0018:ffff888103f3fc88 EFLAGS: 00010282
[  199.130329] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8214d46d
[  199.130733] RDX: 1ffffffff079c6b9 RSI: 0000000000000246 RDI: ffffffff83ce35c8
[  199.131119] RBP: ffff888103d25458 R08: 0000000000000001 R09: fffffbfff0791761
[  199.131505] R10: ffffffff83c8bb07 R11: fffffbfff0791760 R12: 0000000000000000
[  199.131891] R13: ffff888103d25468 R14: ffff888103d25418 R15: ffff888103f18120
[  199.132277] FS:  00007f36fdcbb6a0(0000) GS:ffff88815b400000(0000) knlGS:0000000000000000
[  199.132721] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  199.133033] CR2: 0000000000000010 CR3: 0000000103d26000 CR4: 00000000000006f0
[  199.133420] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  199.133807] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  199.134195] Call Trace:
[  199.134333]  drm_fbdev_cleanup+0x179/0x1a0
[  199.134562]  drm_fbdev_client_unregister+0x2b/0x40
[  199.134828]  drm_client_dev_unregister+0xa8/0x180
[  199.135088]  drm_dev_unregister+0x61/0x110
[  199.135315]  mgag200_pci_remove+0x38/0x52 [mgag200]
[  199.135586]  pci_device_remove+0x62/0xe0
[  199.135806]  device_release_driver_internal+0x148/0x270
[  199.136094]  driver_detach+0x76/0xe0
[  199.136294]  bus_remove_driver+0x7e/0x100
[  199.136521]  pci_unregister_driver+0x28/0xf0
[  199.136759]  __x64_sys_delete_module+0x268/0x300
[  199.137016]  ? __ia32_sys_delete_module+0x300/0x300
[  199.137285]  ? call_rcu+0x3e4/0x580
[  199.137481]  ? fpregs_assert_state_consistent+0x4d/0x60
[  199.137767]  ? exit_to_user_mode_prepare+0x2f/0x130
[  199.138037]  do_syscall_64+0x33/0x40
[  199.138237]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  199.138517] RIP: 0033:0x7f36fdc3dcf7
Signed-off-by: NTong Zhang <ztong0001@gmail.com>
Fixes: 763aea17 ("drm/fb-helper: Unmap client buffer during shutdown")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.11+
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210228044625.171151-1-ztong0001@gmail.comSigned-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

drm_fb_helper_modinit has a lot of boilerplate for what is not very
simple functionality.  Just open code it in the only caller using
IS_ENABLED and IS_MODULE, and skip the find_module check as a
request_module is harmless if the module is already loaded (and not
other caller has this find_module check either).
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJessica Yu <jeyu@kernel.org>

I tried to fix this for real, but it's very sprawling and lots of
drivers get this mildly wrong one way or the other.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Acked-by: NSimon Ser <contact@emersion.fr>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201211161113.3350061-2-daniel.vetter@ffwll.ch

The DRM core handles legacy gamma-set ioctl by setting GAMMA_LUT and
clearing CTM and DEGAMMA_LUT.

This works fine on HW where we have either:

degamma -> ctm -> gamma -> out

or

ctm -> gamma -> out

However, if the HW has gamma table before ctm, the atomic property
should be DEGAMMA_LUT, and thus we have:

degamma -> ctm -> out

This is fine for userspace which sets gamma table using the properties,
as the userspace can check for the existence of gamma & degamma, but the
legacy gamma-set ioctl does not work.

Change the DRM core to use DEGAMMA_LUT instead of GAMMA_LUT when the
latter is unavailable.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201211114237.213288-3-tomi.valkeinen@ti.com

setcmap_legacy() does not call drm_modeset_unlock_all() in some exits,
add the missed unlocks with goto to fix it.

Fixes: 964c6006 ("drm/fb-helper: separate the fb_setcmap helper into atomic and legacy paths")
Signed-off-by: NChuhong Yuan <hslester96@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201203144248.418281-1-hslester96@gmail.com

Flushing the fbdev's shadow buffer requires vmap'ing the BO memory, which
in turn requires pinning the BO. While being pinned, the BO cannot be moved
into VRAM for scanout. Consequently, a concurrent modeset operation that
involves the fbdev framebuffer would likely fail.

Resolve this problem be acquiring the modeset lock of the planes that use
the fbdev framebuffer. On non-atomic drivers, also acquire the mode-config
lock. This serializes the flushing of the framebuffer with concurrent
modeset operations.

v2:
	* only acquire struct drm_fb_helper.lock in damage blitter (Daniel,
	  Christian)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-11-tzimmermann@suse.de

Copy the vmap()'ed instance of struct dma_buf_map before modifying it,
in case the implementation of vunmap() depends on the exact address.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-10-tzimmermann@suse.de

If the damage handling fails, restore the damage area. The next invocation
of the damage worker will then perform the update.

v3:
	* Use drm_WARN_ONCE() with an error message to print warning
v2:
	* print a single warning if dirty callback fails (Daniel, Sebastian)
	* update comment
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-9-tzimmermann@suse.de

Introduce a separate function for the blit code and its vmap setup. Done
in preparation of additional changes. No functional changes are made.

v3:
	* Use drm_WARN_ONCE() with an error message to print warning
v2:
	* print a single warning if damage blitter fails
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-8-tzimmermann@suse.de

Flushing the shadow framebuffer and invoking the dirty callback are two
separate operations, so do them separately. The flush operation is paired
with calls to vmap and vunmap. They are not needed for the dirty callback,
which performs its own invocations if necessary.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-7-tzimmermann@suse.de

Returning early in the damage worker if no update is required. Makes the
code more readable. No functional changes are being made.

v3:
	* s/dirty/damage in commit message (Sam)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-6-tzimmermann@suse.de

The dirty worker handles all damage updates, instead of just calling
the framebuffer's dirty callback. Rename it to damage worker. Also
rename related variables accordingly. No functional changes are made.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-5-tzimmermann@suse.de

The fbdev helper's generic probe function establishes a mapping for
framebuffers without shadow buffer. The clean-up function did not unmap
the buffer object. Add the unmap operation.

As fbdev devices are usally released during system shutdown, this has
not been a problem in practice.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Acked-by: NMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-3-tzimmermann@suse.de

If fbdev uses a shadow framebuffer, call the damage handler. Otherwise
the update might not make it to the screen.

v2:
	* mark virtual screen as dirty (Ville)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Fixes: 222ec45f ("drm/fb_helper: Support framebuffers in I/O memory")
Acked-by: NMaxime Ripard <mripard@kernel.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: virtualization@lists.linux-foundation.org
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-2-tzimmermann@suse.de

On arm32:

    drivers/gpu/drm/drm_fb_helper.c: In function ‘fb_read_screen_base’:
    include/linux/minmax.h:18:28: warning: comparison of distinct pointer types lacks a cast
    ...
    drivers/gpu/drm/drm_fb_helper.c:2041:22: note: in expansion of macro ‘min’
     2041 |  size_t alloc_size = min(count, PAGE_SIZE);
	  |                      ^~~
    drivers/gpu/drm/drm_fb_helper.c: In function ‘fb_write_screen_base’:
    include/linux/minmax.h:18:28: warning: comparison of distinct pointer types lacks a cast
    ...
    drivers/gpu/drm/drm_fb_helper.c:2115:22: note: in expansion of macro ‘min’
     2115 |  size_t alloc_size = min(count, PAGE_SIZE);
	  |                      ^~~

Indeed, on 32-bit size_t is "unsigned int", not "unsigned long".

Fixes: 222ec45f ("drm/fb_helper: Support framebuffers in I/O memory")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201110090119.2667326-1-geert+renesas@glider.be

At least sparc64 requires I/O-specific access to framebuffers. This
patch updates the fbdev console accordingly.

For drivers with direct access to the framebuffer memory, the callback
functions in struct fb_ops test for the type of memory and call the rsp
fb_sys_ of fb_cfb_ functions. Read and write operations are implemented
internally by DRM's fbdev helper.

For drivers that employ a shadow buffer, fbdev's blit function retrieves
the framebuffer address as struct dma_buf_map, and uses dma_buf_map
interfaces to access the buffer.

The bochs driver on sparc64 uses a workaround to flag the framebuffer as
I/O memory and avoid a HW exception. With the introduction of struct
dma_buf_map, this is not required any longer. The patch removes the rsp
code from both, bochs and fbdev.

v7:
	* use min_t(size_t,) (kernel test robot)
	* return the number of bytes read/written, if any (fbdev testcase)
v5:
	* implement fb_read/fb_write internally (Daniel, Sam)
v4:
	* move dma_buf_map changes into separate patch (Daniel)
	* TODO list: comment on fbdev updates (Daniel)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Tested-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-11-tzimmermann@suse.de

Kernel DRM clients now store their framebuffer address in an instance
of struct dma_buf_map. Depending on the buffer's location, the address
refers to system or I/O memory.

Callers of drm_client_buffer_vmap() receive a copy of the value in
the call's supplied arguments. It can be accessed and modified with
dma_buf_map interfaces.

v6:
	* don't call page_to_phys() on framebuffers in I/O memory;
	  warn instead (Daniel)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-9-tzimmermann@suse.de

We didn't take the kernel_fb_helper_lock mutex, which protects that
code. While at it, simplify the code
- inline the function (originally shared with kgdb I think)
- drop the error tracking and all the complications
- drop the pointless early out, it served nothing
Acked-by: NThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007133036.1541639-1-daniel.vetter@ffwll.ch

All slots in sysrq_key_table[] are either used, reserved or at least
commented with their intended use. This patch adds capital letter versions
available, which means adding 26 more entries.

For already existing SysRq operations the user presses Alt-SysRq-<key>, and
for the newly added ones Alt-Shift-SysRq-<key>.
Signed-off-by: NAndrzej Pietrasiewicz <andrzej.p@collabora.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20200818112825.6445-2-andrzej.p@collabora.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Recent kernels have been reported to panic using the bochs_drm
framebuffer under qemu-system-sparc64 which was bisected to
commit 7a0483ac ("drm/bochs: switch to generic drm fbdev emulation").

The backtrace indicates that the shadow framebuffer copy in
drm_fb_helper_dirty_blit_real() is trying to access the real
framebuffer using a virtual address rather than use an IO access
typically implemented using a physical (ASI_PHYS) access on SPARC.

The fix is to replace the memcpy with memcpy_toio() from io.h.

memcpy_toio() uses writeb() where the original fbdev code
used sbus_memcpy_toio(). The latter uses sbus_writeb().

The difference between writeb() and sbus_memcpy_toio() is
that writeb() writes bytes in little-endian, where sbus_writeb() writes
bytes in big-endian. As endian does not matter for byte writes they are
the same. So we can safely use memcpy_toio() here.

Note that this only fixes bochs, in general fbdev helpers still have
issues with mixing up system memory and __iomem space. Fixing that will
require a lot more work.

v3:
  - Improved changelog (Daniel)
  - Added FIXME to fbdev_use_iomem (Daniel)

v2:
  - Added missing __iomem cast (kernel test robot)
  - Made changelog readable and fix typos (Mark)
  - Add flag to select iomem - and set it in the bochs driver
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Reported-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reported-by: Nkernel test robot <lkp@intel.com>
Tested-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200709193016.291267-1-sam@ravnborg.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200725191012.GA434957@ravnborg.org

Change logging information from dev_info() to drm_info().
Signed-off-by: NSuraj Upadhyay <usuraj35@gmail.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/0d37c7a614eb0885f0f0bed18e48a4d26b345a8e.1594136880.git.usuraj35@gmail.com

In the past we had a pile of hacks to orchestrate access between fbdev
emulation and native kms clients. We've tried to streamline this, by
always preferring the kms side above fbdev calls when a drm master
exists, because drm master controls access to the display resources.

Unfortunately this breaks existing userspace, specifically Xorg. When
exiting Xorg first restores the console to text mode using the KDSET
ioctl on the vt. This does nothing, because a drm master is still
around. Then it drops the drm master status, which again does nothing,
because logind is keeping additional drm fd open to be able to
orchestrate vt switches. In the past this is the point where fbdev was
restored, as part of the ->lastclose hook on the drm side.

Now to fix this regression we don't want to go back to letting fbdev
restore things whenever it feels like, or to the pile of hacks we've
had before. Instead try and go with a minimal exception to make the
KDSET case work again, and nothing else.

This means that if userspace does a KDSET call when switching between
graphical compositors, there will be some flickering with fbcon
showing up for a bit. But a) that's not a regression and b) userspace
can fix it by improving the vt switching dance - logind should have
all the information it needs.

While pondering all this I'm also wondering wheter we should have a
SWITCH_MASTER ioctl to allow race-free master status handover. But
that's for another day.

v2: Somehow forgot to cc all the fbdev people.

v3: Fix typo Alex spotted.
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=208179
Cc: shlomo@fastmail.com
Reported-and-Tested-by: shlomo@fastmail.com
Cc: Michel Dänzer <michel@daenzer.net>
Fixes: 64914da2 ("drm/fbdev-helper: don't force restores")
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.7+
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Qiujun Huang <hqjagain@gmail.com>
Cc: Peter Rosin <peda@axentia.se>
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200624092910.3280448-1-daniel.vetter@ffwll.ch