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I've just installed Ubuntu 16.10 on a Lenovo Yoga 910 and have found that when I set the resolution to its native 1920x1080, the display immediately starts flickering and becoming mangled/visually corrupted. Moving the mouse around appears to sometimes make it less horrible, but it's essentially unusable. The same thing happens at the login screen and also when I switch to a different tty.

I'm running the latest Intel i915, updated with the Intel Graphics Update Tool for Linux, and I've tried running with the AccelMethod as both SNA and UXA.

IS there anything I can do to isolate the cause of the problem?

The output of lspci -nnk | grep -iA2 VGA gives me this:

00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:5916] (rev 02)
Subsystem: Lenovo Device [17aa:3801]
Kernel driver in use: i915
nedned
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  • Can you post a picture of your mangled screen? (Taken with a camera, because a screenshot is most likely to look just fine.) – Adrien Beau Dec 15 '16 at 11:07

2 Answers2

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As per this bug, the problem seems to be associated with a power saving feature of the GPU. Disabling this feature through the kernel parameter i915.enable_rc6=0 completely fixed the problem for me.

In my travels, I also found another kernel parameter people have also used to fix screen flickering issues (i915.enable_psr=0), however I didn't need this one.

nedned
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  • nedned - the proposed solution causes my fan to run excessively (and excessively high) on the Yoga 910 running Ubuntu. Do you have that issue as well? Have you revisited this and/or found a different solution? – Rsync Aug 13 '17 at 16:33
  • I haven't noticed this behaviour, and since it's all working fine for me, I haven't looked into any other solutions, sorry! – nedned Aug 14 '17 at 00:25
  • After posting a bug report, I learned that the upstream kernel (v4.13.0-041300rc4-(4.13.0-041300rc4.201708062231) fixes the screen tearing without the need to edit the boot parameter. I still experience more fan use than under 16.04, but it is not as high and not entirely constant. – Rsync Aug 15 '17 at 02:32
  • Scratch that prior post!! The upstream kernel l (v4.13.0-041300rc4-(4.13.0-041300rc4.201708062231) does not fix the problem. Rather, reverting to kernel 4.4 does. I had one to many bourbons when I did uname -r. – Rsync Aug 15 '17 at 02:54
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Here are two things you can try:

  1. Try the other AccelMethod options, that partially or totally disable hardware acceleration: blt or even none. On modern hardware, this may be perfectly usable (did not try it myself).

  2. Actually remove the xserver-xorg-video-intel driver! The Intel driver is made of three parts (the i915 kernel driver, the 3D driver in MESA, and the xserver-xorg-video-intel DDX driver that accelerates 2D rendering under X.Org). When the DDX driver is not installed, X.Org falls back to modesetting, which uses OpenGL to do the acceleration and should work fine on modern hardware.

Note that Debian discourages the use of the Intel DDX driver on post-2007 hardware, so removing it is not as crazy as it seems. I have not tried it myself (but I intend to, because I have issues on a NUC).

Adrien Beau
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  • Thanks heaps for the suggestions. Unfortunately, none of them seemed to help. I guess it does at least show that the problem is not with xserver-xorg-video-intel. – nedned Dec 15 '16 at 10:41
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    Then we need to investigate the i915 driver and its options (kernel command-line). – Adrien Beau Dec 15 '16 at 11:08
  • You are spot on! Just before you posted this comment, I came across an i915 kernel parameter that fixed the problem. See my answer for the details. Thanks for all your help!! – nedned Dec 15 '16 at 11:23