Bug#878221: linux-image-4.9.0-4-amd64: Screen flickers randomly with Radeon R9 270X since upgrade from 4.9.0-3 to 4.9.0-4

2018-01-23 Thread Robin Gareus 
The recent backport kernel does *not* have this issue. All is fine with

 4.14.0-0.bpo.3-amd64 #1 SMP Debian 4.14.13-1~bpo9+1 (2018-01-14)

This is on a Thinkpad X250 with 00:02.0 VGA compatible controller: Intel
Corporation HD Graphics 5500 (rev 09)

4.9.0-4-amd64 and 4.9.0-5-amd64 on the same box do cause screen flickering.



Chances are that the issue was introduced by the update to upstream
4.9.46. There are a handful of "drm/i915" changes:

https://anonscm.debian.org/git/kernel/linux.git/commit/?h=debian/4.9.65-3%2bdeb9u2=17811b5a4b11b32307baca3b88067398a1168cfb

"Workaround VLV/CHV DSI scanline counter hardware fail" sounds
suspicious, but that's just a guess.

Bug#878221: linux-image-4.9.0-4-amd64: Screen flickers randomly since upgrade from 4.9.0-3 to 4.9.0-4

2017-12-21 Thread Robin Gareus 
Same issue with 4.9.0-4-amd64, same workaround (use 4.9.0-3-amd64)

Thinkpad X250
VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09)

What information would be relevant or useful to provide?