drm/i915: Reorder skl+ scaler vs. plane updates

Browse source

When scanning out NV12 if we at any time have the plane enabled
while the scaler is disabled we get a pretty catastrophic
underrun.

Let's reorder the operations so that we try to avoid that happening
even if our vblank evade fails and the scaler enable/disable and
the plane enable/disable get latched during two diffent frames.

This takes care of the most common cases. I suppose there is still
at least a theoretical possibility of hitting this if one plane
takes the scaler away from another plane before the second plane
had a chance to set up another scaler for its use. But that
is starting to get a bit complicated, especially since the plane
commit order already has to be carefully sequenced to avoid any
dbuf overlaps. So plugging this 100% may prove somewhat hard...

Cc: Cooper Chiou <cooper.chiou@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210506073836.14848-1-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

...

This commit is contained in:

Ville Syrjälä 2021-05-06 10:38:36 +03:00

parent e7c46e43bd

commit 7c653e15e2

2 changed files with 30 additions and 11 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

30

drivers/gpu/drm/i915/display/intel_display.c

View file

11

drivers/gpu/drm/i915/display/skl_universal_plane.c

View file