Comment 19 for bug 374413

Forwarding this bug from Ubuntu reporter Gegio0:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/374413

[Problem]
In testing a recent git snapshot of -ati under virtualbox, it was found to cause very bad flickering. No flickering is seen when running with a regular install with no virtualbox.

[Original Description]
I have a LG M227WD widescreen monitor and an integrated ati X1250-based graphics in my Gigabyte MA69GM-S2H motherboard; monitor and graphics are connected through an HDMI cable.

When I am in ubuntu (9.04, fully updated) my monitor blinks to black very often (usually every 3 seconds, but sometimes it blinks even 3-4 times in fast succession) and remains black for about 1 second (again, sometimes it stays black for way more seconds).

On the same machine I have a windows xp installation that works just fine.
Problem seems not to arise in gdm login screen.
I have no xorg.conf file.

Please, consider that this is rendering the ubuntu side of my machine nearly unusable.

I've tested the 1:6.12.99+git20090825.fc74e119 packet for a dozen of hours and I can now say that:
* flickering is almost gone (apart from one flicker just after upgrading and another after a restart, I've seen no other flickering) for classic usage;
but
* flickering is much worse now using virtualbox (I use a windows xp with virtualbox guest additions).

Architecture: i386
DistroRelease: Ubuntu 9.04
Package: xorg 1:7.4~5ubuntu18
ProcEnviron:
 LANG=en_US.UTF-8ProcVersion: Linux versusernamen 2.6.28-11-generic (buildd@palmer) (gcc versusernamen 4.3.3 (Ubuntu 4.3.3-5ubuntu4) ) #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009
SourcePackage: xorg
Uname: Linux 2.6.28-11-generic i686

[lspci]
00:00.0 Host bridge [0600]: ATI Technologies Inc RS690 Host Bridge [1002:7910]
     Subsystem: Giga-byte Technology Device [1458:5000]
01:05.0 VGA compatible controller [0300]: ATI Technologies Inc RS690 [Radeon X1200 Series] [1002:791e]
     Subsystem: Giga-byte Technology Device [1458:d001]