severe graphics flicker for radeon

This affects me also. I have an HP Compaq 6820s with an ATI RV516 (Radeon X1350) graphics card, The same symptoms with the flickering. I notice a small flickering every couple of seconds, and severe flickering at random time periods. Sometimes it comes back to normal, sometimes it doesn't, and I have to reboot.

More details: using kernel 2.6.32-15 this bug disaapears. The bug is present only in 2.6.32-16. Hope this helps.

I've done further testing, and can say:
  2.6.33 --> flicker
  2.6.34 pre rc1 (commit 3474cbd11df8cdd6413781ea95bd51dd469098ff) is good, no flicker.

So at least the problem appears to have been fixed in HEAD. Hopefully the patch will find its way into the 2.6.32 series soon..

And booting with "nomodeset" also seems to prevent flicker, even on 2.6.32-16 or 2.6.33. Of course there are disadvantages to that..

I can confirm the problem on a HP Compaq nx9420 with ATI Radeon Mobility M56P X1600; nomodeset seems to help too.

I can confirm on a Lenovo W500 with an ATI Mobility Radeon HD 3650.
nomodeset fixes for me too.

https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/538648
This bug seems to be a duplicate accept the OP has an Intel card.

Tried 2.6.32-18 : flicker still there; this kernel therefore unusable for me.

I can confirm the same bug on similar (nc8430) hardware on current 2.6.32-19 kernel release. I have returned to the kernel from alpha3.

still present in 2.6.32-20

Try https://bugs.launchpad.net/ubuntu/+source/linux/+bug/537640/comments/10.

Thanks Malthe, the radeon.new_pll=0 setting works fine. No more flickering.

2.6.32-21 fixes this issue for me (without any "raden.new_pll=0").

2.6.32-21 fixed the problem only partially on my HP nc8430 (Radeon X1600):

When I boot up the machine there is no flicker on the internal display and no flicker on dvi. But when I undock the laptop from its docking station and switch from dvi to the internal display via hotkey, the flickering is there, again.

new_pll=1 fixes the flickering problem completely for me.

The new_pll=0 or new_pll=1 has no effect when attaching a second external display. Both screens flicker heavily making the system unusable.
I have a HP Compaq 6820s ( ATI Technologies Inc RV516 [Mobility Radeon X1350] ) and an external Benq G2420HDB 24' external display, and lucid 64bit.
At the moment I'm using the 2.6.32-15 kernel, which seems to work.

On 10.10 (2.6.35-22), the laptop display flickers, while the external monitor looks alright. If I add radeon.new_pll=0 in grub, the flickering disappears.

The problem is also valid for me
ubuntu 10.10, laptop Toshiba
01:00.0 VGA compatible controller: nVidia Corporation G73 [GeForce Go 7600] (rev a1)
2.6.35-22-generic
That looks like nothing with the videocard driver, for me flickering happens on "nouveau" and "proprietary" drive as well.

flickering is heavy especially when used composite WM (Mutter) or opengl (pyopengl programs).
"nomodeset" does not resolve the problem

This affects me on an IBM ThinkCentre
Radeon X1350

amdlin - This bug report is about AMD/ATI Radeon graphics hardware. As you have NVIDIA GeForce hardware, please report a new bug after first searching Launchpad for any existing bug reports about the same problem.

xArchersParadoxx - What kernel version are you using? If you are unsure, please paste the output of uname -srm

Simon Kitching, thank you for reporting this bug and helping make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect 538344

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