[Intel-gfx] [Intel HD 4400] strongly irritating artefacts on 2560x1440 laptop display

[Martin Wilck]

On 01/28/2015 10:45 AM, Chris Wilson wrote:

> From watching the video, and your comments here, it is clear this is not
> a driver bug (neither in the ddx nor opengl compositor). That leaves us
> with hardware misconfiguration, aka kernel bug. Some of the artefacts
> could be a display underrun. It would be good to check a drm.debug=0xe
> dmesg for any warnings (and the info itself will be useful). Another
> thing worth playing with is i915.enable_fbc=1 (though that is really
> just swapping one problem with another).
> -Chris
	
Thanks a lot for looking into this. I uploaded the dmesg to the dropbox
area on
https://www.dropbox.com/sh/9wh0nzvp0w1phxz/AAAsvAqHN8ApXzor58FmGbwLa?dl=0.

I will report the results of playing with the various parameters later.

The defaults (what I've tested so far) are:

enable_cmd_parser: 1
enable_execlists: 0
enable_fbc: -1
enable_hangcheck: Y
enable_ips: 1
enable_ppgtt: 1
enable_psr: 0
enable_rc6: 1

2 more questions to the experts: 1. Would it make sense to check out and
try the latest drm-intel-fixes or drm-intel-next branch? 2. How likely
is it that this phenomenon indicates faulty hardware?

Martin