[Bug 48422] New: Radeon KMS fails on Radeon X850XT (R480) graphics card

[Bug 48422] New: Radeon KMS fails on Radeon X850XT (R480) graphics card

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=48422

             Bug #: 48422
           Summary: Radeon KMS fails on Radeon X850XT (R480) graphics card
    Classification: Unclassified
           Product: DRI
           Version: XOrg 6.7.0
          Platform: x86-64 (AMD64)
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Radeon
        AssignedTo: dri-devel@lists.freedesktop.org
        ReportedBy: mike@coruscant.demon.co.uk


Created attachment 59628
  --> https://bugs.freedesktop.org/attachment.cgi?id=59628
Dmesg output from boot

Video output fails completely (apparently due to a KMS regression) on all
kernels >= 3.2, rendering the system unusable as a desktop. Access via SSH over
network is unaffected.

Steps to reproduce: Boot any recent kernel. This has been encountered with
Debian, and the kernel versions in question are:-

linux-image-3.0.0-2-amd64         3.0.0-5               functions as expected
linux-image-3.2.0-1-amd64         3.2.7-1               fails
linux-image-3.2.0-2-amd64         3.2.13-1              fails
linux-image-3.3.0-trunk-amd64     3.3-1~experimental.1  fails


Expected behaviour:-

At system boot, initial kernel output appears on the VGA console, until the drm
driver is loaded, when the kernel switches the output font and resolution. Boot
continues until a subsequent switch (I believe when the kernel attempts to
modeswitch the card), at which point the font visibly changes at this point and
boot continues, with further console output until the X desktop appears.

Actual behaviour with failing kernels:-

Boot starts normally until the modeswitch happens, at which point video output
ceases, and the monitor shows no signal on the DVI input.

Graphics hardware details from lspci is:-

01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI R480
[Radeon X850XT (PCIE)] (Primary)
01:00.1 Display controller: Advanced Micro Devices [AMD] nee ATI R480 [Radeon
X850XT (PCIE)] (Secondary)

Attached file is dmesg output from booting the 3.3 kernel with drm.debug=0x6
passed as a kernel parameter.

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[Bug 48422] Radeon KMS fails on Radeon X850XT (R480) graphics card

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=48422

--- Comment #1 from Jonathan Nieder <jrnieder@gmail.com> 2012-04-07 12:16:24 PDT ---
Context: http://bugs.debian.org/667799 which mentions that the system is still
usable using ssh after the failed modeset.

Looks like the log with drm.debug=0x6 overflowed the kernel buffer so it's cut
off at the beginning.  Does /var/log/dmesg have more?

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[Bug 48422] Radeon KMS fails on Radeon X850XT (R480) graphics card

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=48422

--- Comment #2 from Mike B <mike@coruscant.demon.co.uk> 2012-04-07 17:07:13 PDT ---
Created attachment 59633
  --> https://bugs.freedesktop.org/attachment.cgi?id=59633
Dmesg output from boot (no drm debug)

Attached file is the dmesg output from booting 3.3 without the drm debug
parameter set.

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[Bug 48422] Radeon KMS fails on Radeon X850XT (R480) graphics card

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=48422

--- Comment #3 from Alex Deucher <agd5f@yahoo.com> 2012-04-09 05:41:43 PDT ---
Should be fixed with this patch:
http://lists.freedesktop.org/archives/dri-devel/2012-April/020963.html

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[Bug 48422] Radeon KMS fails on Radeon X850XT (R480) graphics card

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=48422

Jonathan Nieder <jrnieder@gmail.com> changed:

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

--- Comment #4 from Jonathan Nieder <jrnieder@gmail.com> 2012-04-18 15:13:54 PDT ---
Mike Brodbelt wrote[1]:

> I have done basic testing. Pulling a kernel source tree for 3.3.y and
> applying the patch results in a new kernel which now boots
> successfully.
>
> Currently running kernel is :-
>
> $ uname -a
> Linux mordor 3.3.1+ #5 SMP Tue Apr 10 01:53:45 BST 2012 x86_64 GNU/Linux
>
> Which is working.... I've not tested this tree without the patch yes,
> so can't be 100% certain, but that patch is looking pretty convincing
> so far.

So it looks like this is fixed by

commit afceb9319f21b18ee3bc15ee9a5f92e18ef8a8c9
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Tue Apr 3 17:05:41 2012 -0400

    drm/radeon/kms: fix DVO setup on some r4xx chips

    Some r4xx chips have the wrong frev in the
    DVOEncoderControl table.  It should always be 1
    on r4xx.  Fixes modesetting on DVO on r4xx chips
    with the bad frev.

    Reported by twied on #radeon.

    Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: Dave Airlie <airlied@redhat.com>

which is part of v3.4-rc3.

[1] http://bugs.debian.org/667799#36

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