Apologies if this has been reported already. I always see a black screen (graphics hang?) on logoff with Linux 4.5-rc6 (4.4.3 is fine) on Ubuntu (15.10 and 16.04 beta) with mesa git (oibaf's ppa) on ILK (i3-380M) hardware. I can't reproduce on IVB (Celeron 1007U), HSW (i7-4770R) or SKL (i5-6200U), with the exact same configuration.
i915 platform = ILK
Please attach the full dmesg from boot to logoff (with black screen) having appended drm.debug=0xe to the kernel command line (in grub).
Sure thing, I'll do so tonight, as for now I don't have physical/remote access to the laptop. To be more specific, sometimes the screen is left with some flickering green and/or red pixels on the left side, but otherwise black (the backlight stays on).
Created attachment 122067 [details] dmesg Sorry for the delay. Here's the requested dmesg.
Another data point, yesterday I tested with Linux 4.5-rc7 and mesa git (now only on Ubuntu 16.04) and the problem remains. Without drm.debug=0xe, the last messages on the kernel log are pipe A FIFO underruns. Also, I'm able to switch users, only logoff leads to the black screen.
It's still broken on Linux 4.5 final. I was hoping commit 0bbca274a31c2366414d8d3f95e03d1c4674d93f ("drm/i915: Actually retry with bit-banging after GMBUS timeout") would fix it, but no such luck.
It's still broken on Linux 4.6-rc1, tested yesterday.
Is this issue still seen with latest kernel?
(In reply to Jani Saarinen from comment #8) > Is this issue still seen with latest kernel? Hi, Jani I'm sorry for not following up, I had completely forgotten about this report (which in a certain way is a good thing, I believe :)). Everything has been working fine for months, but I can't say exactly since when. Anyway, I'm closing this one. I'm not sure if I still get those pipe/transcoder A FIFO underruns, but that would be a different issue, for sure. Thanks, Rui
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