Bug 116201

Summary: Freeze during activation of external display on Lenovo X260
Product: Platform Specific/Hardware Reporter: Dennis Wassenberg (dennis.wassenberg)
Component: x86-64Assignee: platform_x86_64 (platform_x86_64)
Status: RESOLVED PATCH_ALREADY_AVAILABLE    
Severity: normal    
Priority: P1    
Hardware: Intel   
OS: Linux   
Kernel Version: 4.5 Subsystem:
Regression: No Bisected commit-id:
Attachments: Default dmesg
drm.debug dmesg

Description Dennis Wassenberg 2016-04-12 08:17:07 UTC 
Created attachment 212441 [details]
Default dmesg

Hi all,

I tried to connect an external display to a Lenovo X260. It doen't matter if it is connected via HDMI or m-DP. Every time I activate the connected display (e.g. Xubuntu - Settings->Display->Select External Display->Use this output) the system will freeze completely. A reboot is possible by holding the power button for 4 seconds only.

It is not possible to get a dmesg output which shows a kernel oops / panic because the cpu seems to stop working completely. I will attach a default dmesg output and a dmesg output with drm.debug. Even trying to create a crash dump via pstore efi backend creates no crash dumps.

To make sure that this issue is not associated with https://bugzilla.kernel.org/show_bug.cgi?id=110941 I added intel_pstate=no_hwp to kernel command line.

Best regards,
Dennis
Comment 1 Dennis Wassenberg 2016-04-12 08:18:04 UTC 
Created attachment 212451 [details]
drm.debug dmesg
Comment 2 Dennis Wassenberg 2016-04-12 11:04:00 UTC 
Some additional information: This freeze will not occur with Ubuntu wily kernel <= 4.4.6. It starts freezing with Ubuntu wily kernel >= 4.5. So maybe it looks like a regression? Using Ubuntu xenial it freezes not dependent on the kernel version. I checked it with default kernel of beta2 (Ubuntu-4.4.0-15) and the latest kernel Ubuntu-4.4.0-18.34.
Comment 3 Dennis Wassenberg 2016-04-29 04:37:48 UTC 
I can not reproduce this crash at drm-intel-nightly since 25th April. So it seems to be fixed now.