Bug#532926: xserver-xorg-video-ati: XRandR multi-monitor: slowness on one screen, acceleration on the other

[Alex Deucher]

On Fri, Jun 12, 2009 at 3:39 PM, Arno Schuring<aelschuring at hotmail.com> wrote:
> Package: xserver-xorg-video-ati Version: 1:6.12.2-2 Severity: normal Short overview: My setup consists of a 17" LCD doing 1280x1024 and a 24" LCD doing 1920x1080 in portrait mode. All drawing updates to the small monitor work fast with hardly any CPU load; xv works as well. Anything that happens on the large monitor immediately spikes CPU usage and takes ages (multiple seconds) to draw. Long version: I recently (today) upgraded from using two 17" panels to one 17" LCD display and a 24" display. In the old situation, both monitors were running 1280x1024 in xrandr side-by-side mode, giving me a large desktop with full acceleration (that is, xv and basic opengl stuff worked fine). When I use only the 24" panel either in landscape or in portrait mode, everything works fine as well. When I use both panels in display clone mode (1080x1920), everything works fine.

Rotation uses the 3D engine so the largest desktop size that can be
rotated with hardware is limited to the max texture size: 2048x2048
for your card.  For desktops larger than that, software is used for
rotation.  1280 + 1920 > 2048.  Due current architectural limitations,
the max size is per-desktop rather than per monitor.

Alex