Comment 0 for bug 1530557

System freezes hard when working under X, sometimes after minutes, sometimes after hours. Usually, but not always, graphics-intensive applications like viewing videos will trigger the hangs after a while, but they can also (much more rarely) occur when e.g. only an xterm is opened and being worked in under Unity.

The MagicSysReq keys are not functional any more once the hang has occurred, there is no information in the logs, and no crash dump can be obtained by using the soft or nmi watchdogs, panic_on_oops etc.

The BIOS was updated to the latest version available from ASUS:

I have tried the latest mainline kernel build from http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D , linux-image-4.4.0-040400rc7-generic_4.4.0-040400rc7.201512272230_amd64.deb (4.4-rc7), and the hangs still occur under the same circumstances.

Some research has led me to https://bugzilla.kernel.org/show_bug.cgi?id=109051 , and I believe that it describes the exact problem I am experiencing. In particular, the workaround mentioned in there. adding the intel_idle.max_cstate=1 kernel option, seems to work for me (and my machine is based on the Intel BayTrail, as mentioned in that report).

(I am writing this report with this option with this enabled now, so don't be surprised to see it in the kernel command line).

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-4.2.0-22-generic 4.2.0-22.27
ProcVersionSignature: Ubuntu 4.2.0-22.27-generic 4.2.6
Uname: Linux 4.2.0-22-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: tmm 2184 F.... pulseaudio
CurrentDesktop: Unity
Date: Sat Jan 2 16:56:51 2016
HibernationDevice: RESUME=UUID=f079f6d2-d58a-474c-ae48-d903be124a02
InstallationDate: Installed on 2015-10-21 (72 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
MachineType: ASUSTeK COMPUTER INC. X751MA
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-22-generic root=UUID=dbe91b1d-f01e-4f19-85eb-3877b67143ac ro quiet splash intel_idle.max_cstate=1 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-22-generic N/A
 linux-backports-modules-4.2.0-22-generic N/A
 linux-firmware 1.149.3
SourcePackage: linux
UpgradeStatus: Upgraded to wily on 2015-10-23 (71 days ago)
dmi.bios.date: 08/10/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: X751MA.403
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: X751MA
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrX751MA.403:bd08/10/2015:svnASUSTeKCOMPUTERINC.:pnX751MA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnX751MA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.name: X751MA
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.