[radeon] vsync is lost after removing a monitor, resulting in tearing

[Daniel van Vugt]

Vsync is lost and significant tearing occurs after removing a monitor. Tested with compiz 0.9.9 revision 3521 on radeon.

Test case:
1. Start with one monitor. Verify no tearing occurs when moving windows.
2. Enable two monitors in the Displays dialog. Verify no tearing occurs on either monitor.
3. Disable (turn off) one monitor in the Display dialog so you're left with only one again.
Expected: No tearing occurs when moving windows.
Observed: Tearing occurs and won't go away until compiz is restarted.

[Daniel van Vugt (vanvugt)]

Actually you don't need to restart compiz to fix the problem. You can get vsync back by just changing VT:
  1. Ctrl+Alt+F1
  2. Ctrl+Alt+F7

This suggests it might be a driver bug (radeon). Haven't tried others yet.

[Daniel van Vugt (vanvugt)]

Invalid for compiz it seems. Assuming it's a driver bug only.

[penalvch (penalvch)]

Daniel van Vugt, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p xserver-xorg-video-ati REPLACE-WITH-BUG-NUMBER

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Launchpad Janitor (janitor)]

[Expired for xserver-xorg-video-ati (Ubuntu) because there has been no activity for 60 days.]