[Bug 35994] New: HP LP2465 screen is cutting in and out after upgrade to linux 2.6.28

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=35994

           Summary: HP LP2465 screen is cutting in and out after upgrade
                    to linux 2.6.28
           Product: xorg
           Version: 7.5
          Platform: Other
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Driver/Radeon
        AssignedTo: xorg-driver-ati at lists.x.org
        ReportedBy: twhitehead at gmail.com
         QAContact: xorg-team at lists.x.org


I have a HP/Compaq 8501w with a "ATI Technologies Inc M76 [Radeon Mobility
HD2600 Series]" graphics card.  It has a HDMI port on the side of it which I
use to plug into a DVI monitor at home and work via a HDMI to DVI cable.

I was running linux 2.6.28 patched with

- bdd91b2b and fb939dfc (to fix 31339), and
- a0ae5864 (to fix 18564).

I upgraded to 2.6.38 and, while my monitor at home continues to work okay, my
monitor at work now has flickering black lines and it cuts in and out to a
black screen.  I did diffs of the kernel logs, xorg logs, and xrandr --verbose
outputs, but nothing seemed to indicate any significant difference.

Finally, I

- checkout out the 2.6.38 kernel from git,
- reverted to bdd91b2b (the first version that had all the above patches), and
- discovered that it also had these problems, 

so I

- did a bisect on any changes that touched the radeon directory between that
and 2.6.26 (cherry picking bdd91b2b, fb939dfc, and a0ae5864 as required), and
- this pointed to 48dfaaeb (drm/radeon/kms: remove new pll algo).

I then did some verification of this by

- attempting to revert 48dfaaeb on top of 2.6.38.

However, this failed as it was not clean and I was not sure of my corrections,
so I instead

- reverted it on top of bdd91b2b (the first version that had all the above
patches)

which produced a driver that worked fine with both monitors.

I presume this then means my monitor at work is having an issue with the pll
settings the old new pll algorithm is generating.  I don't know what
information would be helpful for resolving this though, so I'll just attach

- the kernel logs,
- the xorg logs, and
- the xrandr --verbose logs

for my original patched and working 2.6.36 kernel and the non-working 2.6.38
(although I couldn't see any significant differences in these).  Please let me
know if there is any other information I can provide.

Thanks!  -Tyson

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