https://bugzilla.kernel.org/show_bug.cgi?id=33512
Summary: radeon: lots of time spent in atombios_crtc_disable Product: Drivers Version: 2.5 Kernel Version: 2.6.39-rc3 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: edwintorok@gmail.com Regression: No
Created an attachment (id=54532) --> (https://bugzilla.kernel.org/attachment.cgi?id=54532) dmesg
On a mostly idle system this is what I see with perf top (after exiting a game): --------------------------------------------------------------------------- PerfTop: 386 irqs/sec kernel:72.8% exact: 0.0% [1000Hz cycles], (all, 6 CPUs) ---------------------------------------------------------------------------
samples pcnt function DSO _______ _____ ______________________________ 171.00 18.0% atombios_crtc_disable /lib/modules/2.6.39-rc3-phenom-00117-ge38f5b7/kernel/drivers/gpu/drm/radeon/radeon.ko 47.00 4.9% find_next_bit [kernel.kallsyms] 31.00 3.3% format_decode [kernel.kallsyms]
When playing a game that function is still on top, albeit with a lower percentage (7.5%). If the function does what its name says then it should be called at most once, when switching modes, entering standby, etc. I don't see why it is being called during normal operation, and why is it called so many times that it makes it the top function using the CPU...
The graphics in games is quite laggy too, maybe because of this...
My dmesg is attached.
https://bugzilla.kernel.org/show_bug.cgi?id=33512
--- Comment #1 from Török Edwin edwintorok@gmail.com 2011-04-17 20:45:53 --- Created an attachment (id=54542) --> (https://bugzilla.kernel.org/attachment.cgi?id=54542) Xorg.0.log
Xorg log attached too
https://bugzilla.kernel.org/show_bug.cgi?id=33512
--- Comment #2 from Michel Dänzer michel@daenzer.net 2011-08-05 07:25:50 --- My best guess is that it's page flipping related, but it would be good to confirm that, e.g. by somehow triggering a backtrace from atombios_crtc_disable.
It might also be interesting to add some debugging output to atombios_crtc_disable to narrow down where it's spending so much time. But if my assumption turns out to be true that it keeps getting called on page flips, we might just need to somehow no-op repeated calls.
https://bugzilla.kernel.org/show_bug.cgi?id=33512
--- Comment #3 from Alex Deucher alexdeucher@gmail.com 2011-08-05 13:52:21 --- The only places atombios_crtc_disable() called are from drm_crtc_helper_set_config() and drm_helper_resume_force_mode(). I suspect what is happening is that certain games cause GPU resets which call radeon_gpu_reset() which in turn calls drm_helper_resume_force_mode(). I don't think this is a kernel bug at all. I'd suggest trying a newer mesa if you are using an older version. Try 7.11. Do you see GPU reset messages in your dmesg output after running a problematic game?
https://bugzilla.kernel.org/show_bug.cgi?id=33512
--- Comment #4 from Török Edwin edwintorok@gmail.com 2011-08-05 13:58:50 --- (In reply to comment #3)
I'm using git master now, and it works far better than 7.10 or 7.11.
Do you see GPU reset messages in your dmesg output after running a problematic game?
I didn't look much at perf output lately, will have to try and see if this is still an issue with latest mesa, and report back.
https://bugzilla.kernel.org/show_bug.cgi?id=33512
Alan alan@lxorguk.ukuu.org.uk changed:
What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |alan@lxorguk.ukuu.org.uk Resolution| |OBSOLETE
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