Bug 180041

Summary: i915: A vblank wait timed out on modprobe - cherry trail.
Product: Drivers Reporter: Jonas Aaberg (cja)
Component: Video(AGP)Assignee: Dave Airlie (airlied)
Status: RESOLVED INVALID    
Severity: normal    
Priority: P1    
Hardware: Intel   
OS: Linux   
Kernel Version: 4.8 Subsystem:
Regression: No Bisected commit-id:
Attachments: .config for 4.7.10
.config for 4.8
dmesg 4.7.10
dmesg 4.8
DSDT

Description Jonas Aaberg 2016-10-23 11:30:14 UTC 
On my Asus T100HAN - a cherry trail based computer, the screen goes black when modprobing i915.
dmesg then includes:
--
 WARNING: CPU: 2 PID: 24 at ../drivers/gpu/drm/i915/intel_display.c:13647 intel_atomic_commit_tail+0x19f9/0x1d20 [i915]
pipe A vblank wait timed out
--

On 4.8 it happens every time I modprobe i915, while on 4.7.10 it happens maybe one third of the times.
Comment 1 Jonas Aaberg 2016-10-23 11:30:59 UTC 
Created attachment 242251 [details]
.config for 4.7.10
Comment 2 Jonas Aaberg 2016-10-23 11:31:24 UTC 
Created attachment 242261 [details]
.config for 4.8
Comment 3 Jonas Aaberg 2016-10-23 11:33:33 UTC 
Created attachment 242271 [details]
dmesg 4.7.10

The cpu offline prints are me taking three of four cpus offline to see if that helps.

Please ignore acpi errors about already existing entries. These tables are redundant.
Comment 4 Jonas Aaberg 2016-10-23 11:33:56 UTC 
Created attachment 242281 [details]
dmesg 4.8
Comment 5 Jonas Aaberg 2016-10-23 11:37:13 UTC 
Created attachment 242291 [details]
DSDT
Comment 6 Jani Nikula 2016-10-26 12:38:27 UTC 
Please file all drm/i915 bugs at https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel