[PATCH v2 0/5] drm/fb-helper: Fix and improve fbdevio clipping

Thomas Zimmermann tzimmermann at suse.de
Wed Feb 9 16:16:12 UTC 2022


This is one of several patchset s to improve fb deferred I/O and
DRM's use of it. The patches fix several problems with the current
helpers and add some easy improvements.

Deferred I/O tracks dirty pages of the screen buffer, from which
DRM calculates a bounding box of the damaged area. Patches 1 and 2
resolve bugs in the computation. Specifically, it makes the damage
handling work with overallocation and panning enabled.

Patches 3 to 5 add an easy performance improvement. Instead of
damaging the whole viewport after a write operation, only damage
the written area. For large writes the area consists of multiple
scanlines, for small writes the area might consist of only a few
pixels on a single scanline. Write operations now also work correctly
with overallocation and panning enabled.

v2:
	* rename memory-to-clip helper (Javier)

Thomas Zimmermann (5):
  drm/fb-helper: Fix clip rectangle height
  drm/fb-helper: Fix vertical damage clipping
  drm/fb-helper: Calculate damaged area in separate helper
  drm/fb-helper: Clip damage area to written memory range
  drm/fb-helper: Clip damage area horizontally

 drivers/gpu/drm/drm_fb_helper.c | 69 ++++++++++++++++++++++++++-------
 1 file changed, 54 insertions(+), 15 deletions(-)

-- 
2.34.1



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