[Bug 29726] New: New CRTC ID query breaks Radeon DRM in Zaphod mode

[Bug 29726] New: New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

           Summary: New CRTC ID query breaks Radeon DRM in Zaphod mode
           Product: DRI
           Version: unspecified
          Platform: x86-64 (AMD64)
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Radeon
        AssignedTo: dri-devel@lists.freedesktop.org
        ReportedBy: chewi@aura-online.co.uk


Created an attachment (id=38044)
 --> (https://bugs.freedesktop.org/attachment.cgi?id=38044)
Patch against 2.6.35.3 to remove the offending code

Since upgrading from 2.6.34, programs such as Neverball and MythTV have only
updated the screen while moving the mouse or pressing keys. I managed to bisect
the kernel back to the infamous commit
bc35afdb182d4c48c889fe27ba7a5d7ea0c8194d, along with its related fix
0baf2d8fe43fdd81faa30e65ff71785c99c78520. These add support for querying the
hardware CRTC ID. I knew straight away that this was probably related to me
using Zaphod mode and a test with a single screen did indeed make the problem
go away. There was still the occasional flicker though, which may or may not be
related. I don't get any flickering with the code removed (see attached patch)
while using Zaphod mode.

I knew it was probably related to Zaphod mode because I know that the CRTCs
play a key role there but beyond that, I'm not sure what the problem is. I
don't know exactly what this code is used for.

I probably should have tested two screens without Zaphod mode but my wife will
kill me if I restart the machine again. ;) I'm guessing that isn't affected
because it's a very common setup.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

James Le Cuirot <chewi@aura-online.co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #38044|application/octet-stream    |text/plain
          mime type|                            |
  Attachment #38044|0                           |1
           is patch|                            |

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #1 from James Le Cuirot <chewi@aura-online.co.uk> 2010-08-21 08:45:31 PDT ---
I should add that, despite the similarities, this doesn't seem to be the same
as bug #29327. Booting with pci=nomsi makes no difference for me.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #2 from James Le Cuirot <chewi@aura-online.co.uk> 2010-08-28 07:42:15 PDT ---
Just a note to say that this is NOT fixed as of linux-next-20100827.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #3 from James Le Cuirot <chewi@aura-online.co.uk> 2010-09-18 16:21:02 PDT ---
I have now tested with two monitors, once in "clone" mode and once in "big
desktop" mode and the behaviour is the same as with a single monitor. Just the
occasional flicker. This is definitely related to Zaphod mode.

The problem still present on linux-next-20100917. Please guys, at least explain
the context surrounding this code and where it would be called from. I've seen
some other odd behaviour that could potentially be related to this and it's
really starting to bug me.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

Alex Deucher <agd5f@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lvella@gmail.com

--- Comment #4 from Alex Deucher <agd5f@yahoo.com> 2010-10-24 08:31:13 PDT ---
*** Bug 31066 has been marked as a duplicate of this bug. ***

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #5 from Alex Deucher <agd5f@yahoo.com> 2010-10-24 08:33:15 PDT ---
vblank synchronization apparently does not work correctly in zaphod mode.  You
can disable it by setting the env var vblank_mode=0.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #6 from James Le Cuirot <chewi@aura-online.co.uk> 2010-10-24 16:03:20 PDT ---
I was thinking you actually meant the .drirc setting rather than an actual
environment variable but you were right. Setting this in .drirc makes no
difference but the environment variable does indeed make the problem go away.

I quite like vsyncing so I'm a little sad if it's broken. I think it was
working before?

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #7 from Alex Deucher <agd5f@yahoo.com> 2010-10-24 22:09:03 PDT ---
(In reply to comment #6)
> I was thinking you actually meant the .drirc setting rather than an actual
> environment variable but you were right. Setting this in .drirc makes no
> difference but the environment variable does indeed make the problem go away.
> 

It's works in the .drirc as well, but it requires slightly different handling
for dri2 drivers, e.g.,

<driconf>
    <device screen="0" driver="dri2">
        <application name="Default">
            <option name="vblank_mode" value="0" />
        </application>
    </device>
</driconf>

> I quite like vsyncing so I'm a little sad if it's broken. I think it was
> working before?

It wasn't supported before.  KMS vsync support was added with the commit cited
in this bug.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #8 from James Le Cuirot <chewi@aura-online.co.uk> 2010-10-25 02:11:15 PDT ---
(In reply to comment #7)
> > I quite like vsyncing so I'm a little sad if it's broken. I think it was
> > working before?
> 
> It wasn't supported before.  KMS vsync support was added with the commit cited
> in this bug.

It's been so long since I had a driver with working vsync that I've forgotten
what it looks like. ;)

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #9 from Dave Airlie <airlied@freedesktop.org> 2010-10-27 18:13:16 PDT ---
should be fixed on master DDX now.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

--- Comment #10 from Lucas <lvella@gmail.com> 2010-10-27 19:48:00 PDT ---
(In reply to comment #9)
> should be fixed on master DDX now.

Thank you so much for your commit. The vsync of the proprietary driver was
broken in the second display in new Ubuntu, so I switched to the free driver,
to find it much better than when I last saw it. No way I would go back to
fglrx, but I still could not use the second display (my TV) the way I was used
to (to watch movies, separated displays/screens, vsync on) because of this
bug... I was using big desktop mode until now!

I just tested the driver with the fix, and vsync seemed to work in zaphod mode,
in both screens. DISPLAY=:0.0 is my monitor with 1280x1024 at 60Hz and
DISPLAY=:0.1 is my TV with 1920x1080, also at 60Hz. I played a movie with
mplayer in both screens (gl backend, vsync on) and I could see no visible tear
that was obvious when vsync was off. glxgears is also limited at 60 FPS, as it
should be.

Now I am not sure how to test it without relying on my eye and a movie (I am
satisfied with the result). My test may be unreliable, since I was not able to
shut off vsync in mplayer in a way that I could see the tears I was used to see
with vsync=off in fglrx. Env var vblank_mode=0 shows no artifacts, neither when
running mplayer nor glxgears, although its FPS is not limited at 60 anymore.

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

James Le Cuirot <chewi@aura-online.co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #11 from James Le Cuirot <chewi@aura-online.co.uk> 2010-10-28 03:25:08 PDT ---
(In reply to comment #9)
> should be fixed on master DDX now.

I patched against 6.13.2 and it works great now. Thanks, Dave. :)

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[Bug 29726] New CRTC ID query breaks Radeon DRM in Zaphod mode

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=29726

Alex Deucher <agd5f@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |n0nb@n0nb.us

--- Comment #12 from Alex Deucher <agd5f@yahoo.com> 2011-01-06 15:54:13 PST ---
*** Bug 32885 has been marked as a duplicate of this bug. ***

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