drm/atomic: Fix potential use-after-free in nonblocking commits

This requires a bit of background. Properly done a modeset driver's
unload/remove sequence should be

drm_dev_unplug();
drm_atomic_

drm/atomic: Fix potential use-after-free in nonblocking commits

This requires a bit of background. Properly done a modeset driver's
unload/remove sequence should be

drm_dev_unplug();
drm_atomic_helper_shutdown();
drm_dev_put();

The trouble is that the drm_dev_unplugged() checks are by design racy,
they do not synchronize against all outstanding ioctl. This is because
those ioctl could block forever (both for modeset and for driver
specific ioctls), leading to deadlocks in hotunplug. Instead the code
sections that touch the hardware need to be annotated with
drm_dev_enter/exit, to avoid accessing hardware resources after the
unload/remove has finished.

To avoid use-after-free issues all the involved userspace visible
objects are supposed to hold a reference on the underlying drm_device,
like drm_file does.

The issue now is that we missed one, the atomic modeset ioctl can be run
in a nonblocking fashion, and in that case it cannot rely on the implied
drm_device reference provided by the ioctl calling context. This can
result in a use-after-free if an nonblocking atomic commit is carefully
raced against a driver unload.

Fix this by unconditionally grabbing a drm_device reference for any
drm_atomic_state structures. Strictly speaking this isn't required for
blocking commits and TEST_ONLY calls, but it's the simpler approach.

Thanks to shanzhulig for the initial idea of grabbing an unconditional
reference, I just added comments, a condensed commit message and fixed a
minor potential issue in where exactly we drop the final reference.

Reported-by: shanzhulig <shanzhulig@gmail.com>
Suggested-by: shanzhulig <shanzhulig@gmail.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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drm/connector: Print connector colorspace in state debugfs

v3: Fix kerneldocs (kernel test robot)

v4: Avoid returning NULL from drm_get_colorspace_name

Signed-off-by: Harry Wentland <harry.wentlan

drm/connector: Print connector colorspace in state debugfs

v3: Fix kerneldocs (kernel test robot)

v4: Avoid returning NULL from drm_get_colorspace_name

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com>
Reviewed-by: Joshua Ashton <joshua@froggi.es>
Reviewed-by: Simon Ser <contact@emersion.fr>

Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Melissa Wen <mwen@igalia.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm: add helper functions to retrieve old and new crtc

Add new helper functions, drm_atomic_get_old_crtc_for_encoder
and drm_atomic_get_new_crtc_for_encoder to retrieve the
corresponding crtc for th

drm: add helper functions to retrieve old and new crtc

Add new helper functions, drm_atomic_get_old_crtc_for_encoder
and drm_atomic_get_new_crtc_for_encoder to retrieve the
corresponding crtc for the encoder.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Patchwork: https://patchwork.freedesktop.org/patch/524718/
Link: https://lore.kernel.org/r/1677774797-31063-2-git-send-email-quic_vpolimer@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paala

drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Reviewed-By: Joshua Ashton <joshua@froggi.es>
Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-3-harry.wentland@amd.com
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

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drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paala

drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Reviewed-By: Joshua Ashton <joshua@froggi.es>
Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-3-harry.wentland@amd.com
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

show more ...

drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paala

drm/connector: print max_requested_bpc in state debugfs

This is useful to understand the bpc defaults and
support of a driver.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Reviewed-By: Joshua Ashton <joshua@froggi.es>
Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-3-harry.wentland@amd.com

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drm: use new debugfs device-centered functions on DRM core files

Replace the use of drm_debugfs_create_files() with the new
drm_debugfs_add_files() function in all DRM core files, centering the
debu

drm: use new debugfs device-centered functions on DRM core files

Replace the use of drm_debugfs_create_files() with the new
drm_debugfs_add_files() function in all DRM core files, centering the
debugfs files management on the drm_device instead of drm_minor.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219120621.15086-3-mcanal@igalia.com

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drm/atomic: Constify the old/new state accessors

The drm_atomic_get_(old|new)_*_state don't modify the passed
drm_atomic_state, so we can make it const.

Reviewed-by: Javier Martinez Canillas <javie

drm/atomic: Constify the old/new state accessors

The drm_atomic_get_(old|new)_*_state don't modify the passed
drm_atomic_state, so we can make it const.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20221123-rpi-kunit-tests-v1-9-051a0bb60a16@cerno.tech

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drm: Drop drm_blend.h from drm_crtc.h

drm_crtc.h has no need for drm_blend.h, so don't include it.
Avoids useless rebuilds of the entire universe when
touching drm_blend.h.

Quite a few placs do cur

drm: Drop drm_blend.h from drm_crtc.h

drm_crtc.h has no need for drm_blend.h, so don't include it.
Avoids useless rebuilds of the entire universe when
touching drm_blend.h.

Quite a few placs do currently depend on drm_blend.h without
actually including it directly. All of those need to be fixed
up.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220613200317.11305-4-ville.syrjala@linux.intel.com
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>

show more ...

drm: Drop drm_framebuffer.h from drm_crtc.h

drm_crtc.h has no need for drm_frambuffer.h, so don't include it.
Avoids useless rebuilds of the entire universe when
touching drm_framebuffer.h.

Quite a

drm: Drop drm_framebuffer.h from drm_crtc.h

drm_crtc.h has no need for drm_frambuffer.h, so don't include it.
Avoids useless rebuilds of the entire universe when
touching drm_framebuffer.h.

Quite a few placs do currently depend on drm_framebuffer.h without
actually including it directly. All of those need to be fixed
up.

v2: Fix up msm some more
v2: Deal with ingenic and shmobile as well

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220614095449.29311-1-ville.syrjala@linux.intel.com
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>

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drm/atomic: Add atomic_print_state to private objects

A number of drivers (amdgpu, komeda, vc4, etc.) leverage the
drm_private_state structure, but we don't have any infrastructure to
provide debugg

drm/atomic: Add atomic_print_state to private objects

A number of drivers (amdgpu, komeda, vc4, etc.) leverage the
drm_private_state structure, but we don't have any infrastructure to
provide debugging like we do for the other components state. Let's add
an atomic_print_state hook to be consistent.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220328124304.2309418-3-maxime@cerno.tech

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drm/atomic: Print the state every non-blocking commit

The DRM_UT_STATE controls whether we're calling
drm_atomic_print_new_state() whenever a new state is committed. However,
that call is made in th

drm/atomic: Print the state every non-blocking commit

The DRM_UT_STATE controls whether we're calling
drm_atomic_print_new_state() whenever a new state is committed. However,
that call is made in the drm_mode_atomic_ioctl(), whereas we have
multiple users of the drm_atomic_commit() function in the kernel
(framebuffer emulation, drm_atomic_helper_dirtyfb, etc.).

This leads to multiple states being committed but never actually
displayed even though we asked to have verbose atomic state debugging.

Let's move the call to drm_atomic_print_new_state() to
drm_atomic_commit() to make sure we don't miss any. Non-blocking commits
were never logged though, and it would create too much churn in the logs
to do so, so leave them out for now.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20220328124304.2309418-2-maxime@cerno.tech

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drm/atomic: Add the crtc to affected crtc only if uapi.enable = true

In case of a modeset where a mode gets split across multiple CRTCs
in the driver specific implementation (bigjoiner in i915) we w

drm/atomic: Add the crtc to affected crtc only if uapi.enable = true

In case of a modeset where a mode gets split across multiple CRTCs
in the driver specific implementation (bigjoiner in i915) we wrongly count
the affected CRTCs based on the drm_crtc_mask and indicate the stolen CRTC as
an affected CRTC in atomic_check_only().
This triggers a warning since affected CRTCs doent match requested CRTC.

To fix this in such bigjoiner configurations, we should only
increment affected crtcs if that CRTC is enabled in UAPI not
if it is just used internally in the driver to split the mode.

v3: Add the same uapi crtc_state->enable check in requested
crtc calc (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.11+
Fixes: 919c2299a893 ("drm/i915: Enable bigjoiner")
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211004115913.23889-1-manasi.d.navare@intel.com

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drm: get rid of DRM_DEBUG_* log calls in drm core, files drm_a*.c

DRM_DEBUG_* and DRM_* log calls are deprecated.
Change them to drm_dbg_* / drm_{err,info,...} calls in drm core
files.

To avoid mak

drm: get rid of DRM_DEBUG_* log calls in drm core, files drm_a*.c

DRM_DEBUG_* and DRM_* log calls are deprecated.
Change them to drm_dbg_* / drm_{err,info,...} calls in drm core
files.

To avoid making a very big patch, this change is split in
smaller patches. This one includes drm_a*.c

Signed-off-by: Claudio Suarez <cssk@net-c.es>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/YaC7zXW119tlzfVh@gineta.localdomain

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drm/atomic: Add the crtc to affected crtc only if uapi.enable = true

commit 5ec1cebd59300ddd26dbaa96c17c508764eef911 upstream.

In case of a modeset where a mode gets split across multiple CRTCs
in

drm/atomic: Add the crtc to affected crtc only if uapi.enable = true

commit 5ec1cebd59300ddd26dbaa96c17c508764eef911 upstream.

In case of a modeset where a mode gets split across multiple CRTCs
in the driver specific implementation (bigjoiner in i915) we wrongly count
the affected CRTCs based on the drm_crtc_mask and indicate the stolen CRTC as
an affected CRTC in atomic_check_only().
This triggers a warning since affected CRTCs doent match requested CRTC.

To fix this in such bigjoiner configurations, we should only
increment affected crtcs if that CRTC is enabled in UAPI not
if it is just used internally in the driver to split the mode.

v3: Add the same uapi crtc_state->enable check in requested
crtc calc (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.11+
Fixes: 919c2299a893 ("drm/i915: Enable bigjoiner")
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211004115913.23889-1-manasi.d.navare@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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drm: Fix typo in comments

fix typo for drm

v1->v2:
respin with the change "iff ==> implies that"

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll

drm: Fix typo in comments

fix typo for drm

v1->v2:
respin with the change "iff ==> implies that"

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730132729.376-1-caihuoqing@baidu.com

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drm/plane: check that fb_damage is set up when used

There's two stages of manual upload/invalidate displays:
- just handling dirtyfb and uploading the entire fb all the time
- looking at damage clip

drm/plane: check that fb_damage is set up when used

There's two stages of manual upload/invalidate displays:
- just handling dirtyfb and uploading the entire fb all the time
- looking at damage clips

In the latter case we support it through fbdev emulation (with
fb_defio), atomic property, and with the dirtfy clip rects.

Make sure at least the atomic property is set up as the main official
interface for this. Ideally we'd also check that
drm_atomic_helper_dirtyfb() is used and that fbdev defio is set up,
but that's quite a bit harder to do. Ideas very much welcome.

From a cursor audit drivers seem to be getting this right mostly, but
better to make sure. At least no one is bypassing the accessor
function.

v2:
- use drm_warn_once with a meaningful warning string (José)
- don't splat in the atomic check code for everyone (intel-gfx-ci)

Reviewed-by: José Roberto de Souza <jose.souza@intel.com> (v1)
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Daniel 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/20210723083457.696939-2-daniel.vetter@ffwll.ch

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drm: allow drm_atomic_print_state() to accept any drm_printer

Currently drm_atomic_print_state() internally allocates and uses a
drm_info printer. Allow it to accept any drm_printer type so that
the

drm: allow drm_atomic_print_state() to accept any drm_printer

Currently drm_atomic_print_state() internally allocates and uses a
drm_info printer. Allow it to accept any drm_printer type so that
the API can be leveraged even for taking drm snapshot.

Rename the drm_atomic_print_state() to drm_atomic_print_new_state()
so that it reflects its functionality better.

changes in v5:
- none

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/1618606645-19695-2-git-send-email-abhinavk@codeaurora.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

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drm: drm_atomic.c: Adjust end of block comment

Add a new line with */ on the last line of a block comment to follow the
Linux kernel coding conventions.
Problem found by checkpatch.

Signed-off-by:

drm: drm_atomic.c: Adjust end of block comment

Add a new line with */ on the last line of a block comment to follow the
Linux kernel coding conventions.
Problem found by checkpatch.

Signed-off-by: Beatriz Martins de Carvalho <martinsdecarvalhobeatriz@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/387b6b852a72d6a98133cead5e4d0e3c39dd5094.1618756333.git.martinsdecarvalhobeatriz@gmail.com

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gpu: drm: Replace bare "unsigned" with "unsigned int"

Replaced the type "unsigned" with "unsigned int" because it is
preferred. Issue detected by checkpatch.pl.

Signed-off-by: Fabio M. De Francesco

gpu: drm: Replace bare "unsigned" with "unsigned int"

Replaced the type "unsigned" with "unsigned int" because it is
preferred. Issue detected by checkpatch.pl.

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210412105309.27156-1-fmdefrancesco@gmail.com

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drm/atomic: Couple of typo fixes

s/seralization/serialization/
s/parallism/parallelism/

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signe

drm/atomic: Couple of typo fixes

s/seralization/serialization/
s/parallism/parallelism/

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm: Switch to %p4cc format modifier

Switch DRM drivers from drm_get_format_name() to %p4cc. This gets rid of a
large number of temporary variables at the same time.

Signed-off-by: Sakari Ailus <sa

drm: Switch to %p4cc format modifier

Switch DRM drivers from drm_get_format_name() to %p4cc. This gets rid of a
large number of temporary variables at the same time.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210216155723.17109-4-sakari.ailus@linux.intel.com

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drm: Introduce a drm_crtc_commit_wait helper

There's currently four users of the same logic to wait for a commit to
be flipped: three for the CRTCs, connectors and planes in
drm_atomic_helper_wait_f

drm: Introduce a drm_crtc_commit_wait helper

There's currently four users of the same logic to wait for a commit to
be flipped: three for the CRTCs, connectors and planes in
drm_atomic_helper_wait_for_dependencies, and one in vc4.

Let's consolidate this a bit to avoid any code duplication.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111084401.117152-1-maxime@cerno.tech

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drm: atomic: use krealloc_array()

Use the helper that checks for overflows internally instead of manually
calculating the size of the new array.

Link: https://lkml.kernel.org/r/20201109110654.12547

drm: atomic: use krealloc_array()

Use the helper that checks for overflows internally instead of manually
calculating the size of the new array.

Link: https://lkml.kernel.org/r/20201109110654.12547-8-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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drm/atomic: document and enforce rules around "spurious" EBUSY

When doing an atomic modeset with ALLOW_MODESET drivers are allowed to
pull in arbitrary other resources, including CRTCs (e.g. when
re

drm/atomic: document and enforce rules around "spurious" EBUSY

When doing an atomic modeset with ALLOW_MODESET drivers are allowed to
pull in arbitrary other resources, including CRTCs (e.g. when
reconfiguring global resources).

But in nonblocking mode userspace has then no idea this happened,
which can lead to spurious EBUSY calls, both:
- when that other CRTC is currently busy doing a page_flip the
ALLOW_MODESET commit can fail with an EBUSY
- on the other CRTC a normal atomic flip can fail with EBUSY because
of the additional commit inserted by the kernel without userspace's
knowledge

For blocking commits this isn't a problem, because everyone else will
just block until all the CRTC are reconfigured. Only thing userspace
can notice is the dropped frames without any reason for why frames got
dropped.

Consensus is that we need new uapi to handle this properly, but no one
has any idea what exactly the new uapi should look like. Since this
has been shipping for years already compositors need to deal no matter
what, so as a first step just try to enforce this across drivers
better with some checks.

v2: Add comments and a WARN_ON to enforce this only when allowed - we
don't want to silently convert page flips into blocking plane updates
just because the driver is buggy.

v3: Fix inverted WARN_ON (Pekka).

v4: Drop the uapi changes, only add a WARN_ON for now to enforce some
rules for drivers.

v5: Make the WARNING more informative (Daniel)

v6: Add unconditional debug output for compositor hackers to figure
out what's going on when they get an EBUSY (Daniel)

v7: Fix up old/new_crtc_state confusion for real (Pekka/Ville)

Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
References: https://lists.freedesktop.org/archives/dri-devel/2018-July/182281.html
Bugzilla: https://gitlab.freedesktop.org/wayland/weston/issues/24#note_9568
Cc: Daniel Stone <daniel@fooishbar.org>
Cc: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Cc: Simon Ser <contact@emersion.fr>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200925084651.3250104-1-daniel.vetter@ffwll.ch

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