[Bug 538344] [NEW] severe graphics flicker for radeon

[Simon Kitching]

Public bug reported:

When booting Lucid with linux-image-2.6.32-14, graphics works fine.

But booting with 2.6.32-16 triggers nasty flickering.

Weirdly, the flickering does not happen immediately. If I boot the bad
kernel from a "cold" system then the login screen displays fine. Without
doing anything (no login, etc), after about 30 seconds mild flickering
starts, and gets progressively worse. After about 2 minutes system is
unusable. Same happens if I log in.

If I shutdown and immediately restart, the flickering is there
immediately. But if I shutdown, wait 10 mins or so, then restart then
the flickering does not begin for 30 seconds or so.

So it is perhaps something related to power-management in the ATI Radeon
driver?

System details:
HP Compaq nc8430 laptop, Core Duo T2500 at 2ghz
ATI Radeon Mobility M56P X1600, running at 1680x1050, 60hz

More detail about flickering: the screen appears to lose "vertical
sync", redisplaying at various vertical offsets for a few frames.
Initially, it displays the screen mostly correct with just a few
"displaced" frames per second. Then it progresses to where just about
every frame is displaced at some random vertical offset from where it
should be, effectively "flickering" madly up and down.

There is nothing odd in dmesg.

I'm happy to test patches, try reconfiguration etc. Just let me know
what..

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

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severe graphics flicker for radeon
https://bugs.launchpad.net/bugs/538344
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