[PATCH 0/1][SRU][Focal] Dell XPS 13 9300 mirror mode doesn't work sometimes with WD19TB

[AceLan Kao]

BugLink: https://bugs.launchpad.net/bugs/1877013

[Impact]
Connect HDMI monitor on WD19TB dock and connect WD19TB to Dell XPS 13
9300, toggling the display mode to mirror sometimes got a blank screen on
external monitor.

[Fix]
After bisect kernel and found below commit(from v5.7-rc2) improves the
stability
bcad588dea53 drm/i915/perf: Do not clear pollin for small user read buffers

[Test]
Verified on Dell XPS 13 9300 with WD19TB docking station, the fail rate
becomes from 1/2 to 1/30

[Regression Potential]
Low, this commit has been CC'd to stable, so we will have this soon.

[Misc]
OEM-5.6 has this commit from v5.6.6 stable update

Ashutosh Dixit (1):
  drm/i915/perf: Do not clear pollin for small user read buffers

 drivers/gpu/drm/i915/i915_perf.c | 65 ++++++--------------------------
 1 file changed, 11 insertions(+), 54 deletions(-)

-- 
2.25.1