Random hard freezes under X on a laptop with Intel BayTrail processor (ASUS R752MA)

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Thomas Moestl, thank you for reporting this and helping make Ubuntu better.

To see if this has been addressed in the upstream release, could you please test the latest drm-intel-nightly via http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/ and advise to the results?

Thanks!

I have tried the newest available build from drm-intel-nightly, linux-image-4.4.0-994-generic_4.4.0-994.201512302100_amd64.deb :

> cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.4.0-994-generic root=UUID=dbe91b1d-f01e-4f19-85eb-3877b67143ac ro quiet splash vt.handoff=7

Unfortunately it just froze again, same as before, after about 45min of uptime.

Thomas Moestl, to clarify, did this issue not occur in a release prior to 15.10?

Hmmm, I don't remember, actually. When I got this machine, I installed from a 14.04 DVD, but immediately updated to 15.10 via 15.04 before I even really started using it. I don't remember it having hung in the few hours I had it run on 14.04 or 15.04 while setting things up, but I could be wrong.
I noticed it pretty much immediately once I had 15.10 running, but it was much rarer then and I did not have time to go bug hunting immediately.

If it helps, however, I can confirm that the issue occurs with linux-image-extra-3.19.0-31-generic (version 3.19.0-31.36), as well, which is the latest image that is installed via linux-image-generic-lts-vivid on 15.10.

Just as an addendum, the machine is stable when booted into Win 8.1, even under heavy graphics loads such as games, and now is under Ubuntu as well with intel_idle.max_cstate=1 , so I believe that hardware flakiness is unlikely to be the cause (especially since a lot of people are reporting the same issue, amenable to the same workaround, on a variety of different BayTrail-based hardware in the above kernel.org bug report).

Thomas Moestl, the issue you are reporting is an upstream one. Could you please report this problem following the instructions verbatim at https://wiki.ubuntu.com/Bugs/Upstream/kernel to the appropriate mailing list (TO Len Brown CC linux-pm)?

Please provide a direct URL to your post to the mailing list when it becomes available so that it may be tracked.

Thank you for your understanding.

As topic says it, ASUS R752MA is Bay Trail based so could be same cause:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1531865

I built Ubuntu-4.2.0-23.28 with "drm/i915: Agressive downclocking on Baytrail" reversed and it can be found from here:

http://www.helsinki.fi/~jmoheikk/baytrail/

If you could test whether it works or not.

I have tested Janne's kernel, but am still experiencing the freezes, even though they have become more rare.

I have now finally sent a problem report to Len Brown and linux-pm (sorry for the delay, wanted to test Janne's kernel before I did to make sure, and also had to test on 4.4rc8, which has come out in the meantime, so that my report would be for the lastest release).

Here's a link to the message on linux-pm:
http://marc.info/?l=linux-pm&m=145237874906192&w=2

What software did you use to watch videos when these hangs occurred?

I've now been able to hang 4.4rc8 with OpenGL 3.0 code that draws about 70 million triangles per second. I haven't been able to hang it with streaming video from the web or playing MPEG4 (ripped dvd's) video with VLC. And so far I haven't been able to hang 4.2.8 at all. And I've been testing only kernels with "drm/i915: Agressive downclocking on Baytrail" reversed, ie. no "intel_idle.max_cstate=1". I'm wondering if another player and/or more demanding video (full HD) would made playback hang for me.

After updating from 14.04 LTS to 16.04 LTS I see the same issue with Intel J1900 (also baytrail) and the current standard amd64 kernel 4.4.0-34. Video freezes and no input reaches the system any more. No possibility to get out of the deadlock, no keyboard and no further logs produced.

Some research pointed me to other users with the same problem, the initial description matches the case and is quite likely what Thomas Moestl also sees:

http://askubuntu.com/questions/761706/ubuntu-15-10-and-16-04-keep-freezing-randomly

I manually installed Kernel 4.7.0-040700rc3-generic #201606121131 SMP Sun Jun 12 15:34:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux and can confirm that the issue is solved with this. Unfortunately the current regular kernel does not work, but according to https://bugzilla.kernel.org/show_bug.cgi?id=109051 there is no definitive fix for this yet

as the j1900 and the processor op uses are both listed in the Intel errata, I guess it is really related to the c6 states hardware bug. https://bugzilla.kernel.org/show_bug.cgi?id=109051#c436 I will try to disable c6 states as described there and see whether this works with the current standard kernel (which hasn't worked before)

We have a large number of laptops running 16.04 impacted by this bug. The initial testing after disabling c6 states has been very promising. We are deploying that fix now. Here is the script for reference: https://bugzilla.kernel.org/attachment.cgi?id=223851

I will update this bug report after some more time has past.