drm/todo: Add entry for moving to dma_resv_lock

Requested by Thomas. I think it justifies a new level, since I tried
to make some forward progress on this last summer, and gave up (for
now). This is very tricky.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
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>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210122133624.1751802-1-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter 2021-01-22 14:36:23 +01:00
parent 09b20988ff
commit 5823cca39d
1 changed files with 19 additions and 0 deletions

View File

@ -23,6 +23,9 @@ Advanced: Tricky tasks that need fairly good understanding of the DRM subsystem
and graphics topics. Generally need the relevant hardware for development and
testing.
Expert: Only attempt these if you've successfully completed some tricky
refactorings already and are an expert in the specific area
Subsystem-wide refactorings
===========================
@ -168,6 +171,22 @@ Contact: Daniel Vetter, respective driver maintainers
Level: Advanced
Move Buffer Object Locking to dma_resv_lock()
---------------------------------------------
Many drivers have their own per-object locking scheme, usually using
mutex_lock(). This causes all kinds of trouble for buffer sharing, since
depending which driver is the exporter and importer, the locking hierarchy is
reversed.
To solve this we need one standard per-object locking mechanism, which is
dma_resv_lock(). This lock needs to be called as the outermost lock, with all
other driver specific per-object locks removed. The problem is tha rolling out
the actual change to the locking contract is a flag day, due to struct dma_buf
buffer sharing.
Level: Expert
Convert logging to drm_* functions with drm_device paramater
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