Bug 20296 - vblank interrupts at startup after kernel upgrade (2.6.28)
Summary: vblank interrupts at startup after kernel upgrade (2.6.28)
Status: RESOLVED FIXED
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: 7.4 (2008.09)
Hardware: Other All
: medium normal
Assignee: Jesse Barnes
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-02-24 09:02 UTC by Alberto González
Modified: 2009-03-30 17:24 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Attachments

Description Alberto González 2009-02-24 09:02:25 UTC
After upgrading to kernel 2.6.28 I see about 60-100 extra wakeups as reported by Powertop coming from i915@pci... interrupts (the problem doesn't happen with kernel 2.6.27).

It happens on my two machines using Intel graphics (a 5 year old Pentuim 4 using i845G chipset and new Core 2 Duo using G45 chip).

It only happens when booting directly into X. If I bootup to console and start X manually, no problem. Also th problem goes away switching to console and back to X (or suspending to disk or RAM and waking up).

References:
http://bugzilla.kernel.org/show_bug.cgi?id=12337
http://marc.info/?l=linux-kernel&m=123547283726418&w=2

I'm using xserver-1.5.3 and xf86-video-intel-2.4.3.
Comment 1 Alberto González 2009-02-24 11:05:44 UTC
I upgraded to xf86-video-intel 2.6.1 (also had to upgrade liddrm to 2.4.5 and install libpthread-stubs) and the problem persisted (about 140 wakeups this time).

Switching to console and trying to go back to X hard locked the system, so I can't verify the problem goes away doing so.
Comment 2 Alberto González 2009-03-14 15:29:32 UTC
A small update: I just tested using UXA (instead of EXA) and that makes the problem disappear.
Comment 3 Jesse Barnes 2009-03-30 17:24:17 UTC
Since EXA probably won't be supported going forward, I'll close this out as fixed since UXA doesn't have the problem.  Thanks for reporting.


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