[PATCH v2 00/10] drm/fb-helper: Various fixes and cleanups

Thomas Zimmermann tzimmermann at suse.de
Fri Nov 20 10:25:35 UTC 2020


Here's a number of fb-helper patches that have been piling up recently.

Patches 1 to 3 fix bugs that I spotted while going through the code.
Because of the way the fbdev code works, they have been avoided so far.

Patches 4 to 10 cleanup damage handling for fbdev's shadow buffer and
fix a few issues.

Specifically, the final patch adds locking to the code that flushes the
shadow framebuffer into BO memory. During the conversion of radeon to
generic fbdev, the question came up about interference with concurrent
modesets. If fbdev has the BO pinned in system memory for flushing while
the modeset wants to pin it to VRAM for scanout, the modeset would
most likely fail. We haven't seen that so far, but it's possible at
least. Acquiring the fb-helper lock during the flush operation prevents
concurrent modesets from taking place.

The code has been tested with SHMEM and TTM BOs; with atomic and non-
atomic modesetting.

[1] https://patchwork.freedesktop.org/patch/400054/?series=83765&rev=1

Thomas Zimmermann (10):
  drm/fb-helper: Call dirty helper after writing to fbdev
  drm/fb-helper: Unmap client buffer during shutdown
  drm/client: Depend on GEM object kmap ref-counting
  drm/fb-helper: Rename dirty worker to damage worker
  drm/fb-helper: Return early in dirty worker
  drm/fb-helper: Separate shadow-buffer flushing and calling dirty
    callback
  drm/fb-helper: Move damage blit code and its setup into separate
    routine
  drm/fb-helper: Restore damage area upon errors
  drm/fb-helper: Copy dma-buf map before flushing shadow fb
  drm/fb-helper: Acquire modeset lock around shadow-buffer flushing

 drivers/gpu/drm/drm_client.c    |   4 -
 drivers/gpu/drm/drm_fb_helper.c | 155 +++++++++++++++++++++-----------
 include/drm/drm_fb_helper.h     |  14 +--
 3 files changed, 108 insertions(+), 65 deletions(-)

--
2.29.2



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