[Bug 33512] New: radeon: lots of time spent in atombios_crtc_disable

[Bug 33512] New: radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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.

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[Bug 33512] radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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

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[Bug 33512] radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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.

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[Bug 33512] radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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?

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[Bug 33512] radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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)
> 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.

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.

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[Bug 33512] radeon: lots of time spent in atombios_crtc_disable

[bugzilla-daemon]

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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