[barthand]

Hi Guys,

I have Asrock J3455-ITX and I am using Ubuntu 16.10 with Mesa 17.1 (and all VAAPI and Intel goodies) installed from Padoka PPA.
I'm experiencing issues with my display while running 4k@60Hz (only! lower frequencies seems to work fine) and I would be very grateful if anyone could tell me if encounters the same.

Problems I'm having start from screen flickering from time to time - screen goes completely black for a second or two, then is okay for next few seconds and then it flickers again. Just to be clear: this happens to me not only while playing video content, but also in Kodi UI and sometimes even in Unity itself. Sometimes this problem starts right after playing the content, sometimes even right away after booting OS, but it happens also this doesn't show up for a longer while.

The problem disappears as soon as I switch to 24Hz - flickering is gone then. Problem is only on 4K resolution at 60Hz only.

After having flickering, often other graphics artifacts or glitches start to appear such as horizontal solid-color lines flying over the screen. In this case, I need to either restart X server (sometimes helps, not always) or reboot the box.

Software used:
Mesa 17.1, libva 1.8.0.pre1, i965 driver 1.8.1.pre1 (freshly updated and aligned with Padoka PPA)
Kernels - tried 4.8.0(-45) line as provided by Ubuntu, 4.9.13, 4.10.0-997 and 4.11.0-994 (Ubuntu's drm-intel-next)

Hardware used: ASRock J3455-ITX with BIOS 1.20, haven't updated HDMI firmware so far (no Windows installed...)

Is anyone experiencing similar problem? Maybe you have any suggestions about possible root cause?
Where do you think I should seek help (mesa-dev mailing lists? Asrock support forums)? I guess it is not impossible also that it's a hardware problem..

In case any logs are required, please just let me know (although I wasn't able to find anything interesting in Xorg.0.log so far).

Many (many!) thanks in advance.

P.S. On Mesa 17.0 and older intel drivers (installed as standard in Ubuntu) I wasn't able to run 4K@60Hz at all, so I can't easily tell if that's Mesa/drivers issue.