Bug 95045

Summary: Driver randomly hangs in sna_wait_vblank()
Product: xorg Reporter: Mikołaj Siedlarek <mikolaj>
Component: Driver/intelAssignee: Chris Wilson <chris>
Status: RESOLVED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium CC: mikolaj
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
log from Xorg initialization
none
trace from GDB none

Description Mikołaj Siedlarek 2016-04-20 22:48:33 UTC 
Created attachment 123102 [details]
log from Xorg initialization

Machine: Apple MacBook Pro Retina 10.1
OS: Linux 4.5.1-1-ARCH #1 SMP PREEMPT x86_64 GNU/Linux
Graphics: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
Xorg Server: 1.18.3
Xorg Intel Driver: 2.99.917 (commit f2a4645)

Xorg randomly and permanently hangs in Intel driver using SNA on my machine,
with main thread eating up 100% of one CPU core. Couple of semi-random manual
breaks in a debugger show the driver spending all of this time in sna_wait_vblank()
function.

Mouse cursor also freezes if that matters - I saw people posting this in their
bug reports.

I'm attaching:
- backtrace from GDB
- log from Xorg initialization (rest of the log was from libinput, so I cut it out)
Comment 1 Mikołaj Siedlarek 2016-04-20 22:49:05 UTC 
Created attachment 123103 [details]
trace from GDB
Comment 2 Chris Wilson 2016-04-20 23:19:17 UTC 
commit 29b70ccdf67ee7afa19bed26de8678476ba94f6e
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Sun Apr 17 15:02:46 2016 +0100

    sna/present: Fix requeuing after interrupting TearFree

commit 562ae1f29fd4946c5204bacc9eaa4ee13e809753
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Apr 18 20:56:05 2016 +0100

    sna/present: Postpone recursed vblank during TearFree by 1ms

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