linux-stable.git/drivers/gpu/drm/drm_file.c, branch linux-5.15.y

drm/drm_file: fix use of uninitialized variable

2024-02-23T07:54:46+00:00

[ Upstream commit 1d3062fad9c7313fff9970a88e0538a24480ffb8 ]

smatch reports:

drivers/gpu/drm/drm_file.c:967 drm_show_memory_stats() error: uninitialized symbol 'supported_status'.

'supported_status' is only set in one code path. I'm not familiar with
the code to say if that path will always be ran in real life, but
whether that is the case or not, I think it is good to initialize
'supported_status' to 0 to silence the warning (and possibly fix a bug).

Reviewed-by: Laurent Pinchart 
Acked-by: Maxime Ripard 
Signed-off-by: Tomi Valkeinen 
Link: https://patchwork.freedesktop.org/patch/msgid/20231103-uninit-fixes-v2-1-c22b2444f5f5@ideasonboard.com
Signed-off-by: Sasha Levin

drm: Fix typo in comments

2021-08-02T08:19:43+00:00

fix typo for drm

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

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

drm: serialize drm_file.master with a new spinlock

2021-07-20T18:17:58+00:00

Currently, drm_file.master pointers should be protected by
drm_device.master_mutex when being dereferenced. This is because
drm_file.master is not invariant for the lifetime of drm_file. If
drm_file is not the creator of master, then drm_file.is_master is
false, and a call to drm_setmaster_ioctl will invoke
drm_new_set_master, which then allocates a new master for drm_file and
puts the old master.

Thus, without holding drm_device.master_mutex, the old value of
drm_file.master could be freed while it is being used by another
concurrent process.

However, it is not always possible to lock drm_device.master_mutex to
dereference drm_file.master. Through the fbdev emulation code, this
might occur in a deep nest of other locks. But drm_device.master_mutex
is also the outermost lock in the nesting hierarchy, so this leads to
potential deadlocks.

To address this, we introduce a new spin lock at the bottom of the
lock hierarchy that only serializes drm_file.master. With this change,
the value of drm_file.master changes only when both
drm_device.master_mutex and drm_file.master_lookup_lock are
held. Hence, any process holding either of those locks can ensure that
the value of drm_file.master will not change concurrently.

Since no lock depends on the new drm_file.master_lookup_lock, when
drm_file.master is dereferenced, but drm_device.master_mutex cannot be
held, we can safely protect the master pointer with
drm_file.master_lookup_lock.

Reported-by: Daniel Vetter
Signed-off-by: Desmond Cheong Zhi Xi
Signed-off-by: Daniel Vetter
Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-5-desmondcheongzx@gmail.com

drm/drm_file.c: Define drm_send_event_helper() as 'static'

2021-04-27T12:23:12+00:00

drm_send_event_helper() has not prototype, it has internal linkage and
therefore it should be defined with storage class 'static'.

Signed-off-by: Fabio M. De Francesco 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20210427105503.10765-1-fmdefrancesco@gmail.com

drm/drm_vblank: set the dma-fence timestamp during send_vblank_event

2021-01-22T10:52:29+00:00

The explicit out-fences in crtc are signaled as part of vblank event,
indicating all framebuffers present on the Atomic Commit request are
scanned out on the screen. Though the fence signal and the vblank event
notification happens at the same time, triggered by the same hardware
vsync event, the timestamp set in both are different. With drivers
supporting precise vblank timestamp the difference between the two
timestamps would be even higher. This might have an impact on use-mode
frameworks using these fence timestamps for purposes other than simple
buffer usage. For instance, the Android framework [1] uses the
retire-fences as an alternative to vblank when frame-updates are in
progress. Set the fence timestamp during send vblank event using a new
drm_send_event_timestamp_locked variant to avoid discrepancies.

[1] https://android.googlesource.com/platform/frameworks/native/+/master/
services/surfaceflinger/Scheduler/Scheduler.cpp#397

Changes in v2:
- Use drm_send_event_timestamp_locked to update fence timestamp
- add more information to commit text

Changes in v3:
- use same backend helper function for variants of drm_send_event to
avoid code duplications

Changes in v4:
- remove WARN_ON from drm_send_event_timestamp_locked

Signed-off-by: Veera Sundaram Sankaran 
Reviewed-by: John Stultz 
Signed-off-by: Sumit Semwal 
  [sumits: minor parenthesis alignment correction]
Link: https://patchwork.freedesktop.org/patch/msgid/1610757107-11892-2-git-send-email-veeras@codeaurora.org

drm: Move struct drm_device.hose to legacy section

2021-01-13T13:22:37+00:00

The field is only relevant for legacy DRM drivers. Its only non-legacy
user in the DRM core is in drm_file.c. This code is now protected by
CONFIG_DRM_LEGACY. Radeon, the only driver that used the field, has been
changed to maintain it's own copy.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Christian König 
Link: https://patchwork.freedesktop.org/patch/msgid/20210112081035.6882-7-tzimmermann@suse.de

drm: Removes invalid function return value comment information

2021-01-12T08:56:47+00:00

Signed-off-by: Zhaoge Zhang 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/1610415567-32171-1-git-send-email-zhangzhaoge@loongson.cn

drm/cma-helper: Implement mmap as GEM CMA object functions

2020-11-30T12:38:27+00:00

The new GEM object function drm_gem_cma_mmap() sets the VMA flags
and offset as in the old implementation and immediately maps in the
buffer's memory pages.

Changing CMA helpers to use the GEM object function allows for the
removal of the special implementations for mmap and gem_prime_mmap
callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
are now used.

Signed-off-by: Thomas Zimmermann 
Acked-by: Maxime Ripard 
Link: https://patchwork.freedesktop.org/patch/msgid/20201123115646.11004-3-tzimmermann@suse.de

drm: Compile out legacy chunks from struct drm_device

2020-11-06T09:31:26+00:00

This means some very few #ifdef in code, but it allows us to
enlist the compiler to make sure this stuff isn't used anymore.

More important, only legacy drivers change drm_device (for the
legacy_dev_list shadow attach management), therefore this is
prep to allow modern drivers to have a const driver struct. Which
is nice, because there's a ton of function pointers in there.

Acked-by: Maxime Ripard 
Reviewed-by: Sam Ravnborg 
Review-by: Thomas Zimmermann 
Reviewed-by: Alex Deucher 
Signed-off-by: Daniel Vetter 
Cc: Sam Ravnborg 
Cc: Maarten Lankhorst 
Cc: Maxime Ripard 
Cc: Thomas Zimmermann 
Cc: David Airlie 
Cc: Daniel Vetter 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20201104100425.1922351-2-daniel.vetter@ffwll.ch

drm : Insert blank lines after declarations.

2020-07-02T13:26:00+00:00

Resolve checkpatch issues for missing blank lines after declarations.
Issues found in multiple files with checkpatch.pl.

Signed-off-by: Suraj Upadhyay 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20200702131749.GA25710@blackclown