Fujitsu-Siemens Lifebook S6420 with Lifebook port replicator 

  ------- Comment  #24 From Tony Vroon  2009-06-22 09:49:39 PST  [reply] -------

As frustration set in, I attached a different monitor (Samsung SyncMaster
2243BW) with a native resolution of 1680x1050. Aside from ruling out the
monitor as the cause of the strange DVI/HDMI timings and corruption... I just
captured an interesting set of register dumps (if you diff them, it almost
looks as if some bits got cleared/set that should not have been). I'll defer to
you as to whether you'd like the original ViewSonic attached again, but this
seemed worth sharing.

 ------- Comment  #27 From Tony Vroon  2009-06-25 01:16:16 PST  [reply] -------  

Correct, in UMS the monitor is driven correctly. In KMS, generally the screen
stays black at 1680x1050 while at lower resolutions the image is corrupted
(either with moving lines or by the image being off-centre & cut in half).

Created attachment 27602 [details]
kms regdump with samsung monitor, broken

Created attachment 27603 [details]
regdump ums with samsung monitor, good

After comparing two register dump, I think the issue is from
commit 5ca58282089b11f64b911618036ee7676f12735b
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Tue Mar 31 14:11:15 2009 -0700
which caused ADPA is enabled.

It has been resolved by 
commit febc7694a55277b70cd662de05ed8a957685959c
Author: ling.ma@intel.com <ling.ma@intel.com>
Date:   Thu Jun 25 11:55:57 2009 +0800

    drm/i915: Disable VGA output when doing DRM_MODE_DPMS_OFF.

    Signed-off-by: Ma Ling <ling.ma@intel.com>
    Signed-off-by: Eric Anholt <eric@anholt.net>

Thanks
Ma Ling

Tony, could you please help verify? thanks.

(In reply to comment #5)
> Tony, could you please help verify? thanks.

ping ~

Created attachment 27950 [details]
regdump.samsung.rc3.txt

Confirmed, this issue is no longer present in 2.6.31-rc3-00157-gaea1f79. Output looks good, regdump attached (for KMS). Thank you :)

looks like a resolved bug then.