Bug#621666: xserver-xorg-video-radeon: video playback only displays/updates on one monitor when both are enabled with xrandr

Michel Dänzer daenzer at debian.org
Mon Apr 11 01:43:07 PDT 2011

On Fre, 2011-04-08 at 17:07 -0400, Daniel Kahn Gillmor wrote: 
> On 04/08/2011 07:26 AM, Michel Dänzer wrote:
> > This is probably due to using the XVideo overlay adaptor. The display
> > hardware can only display the video overlay on one CRTC at a time. You
> > can choose which CRTC to display it on via the XV_CRTC XVideo attribute,
> > or at least some applications allow using the textured video adaptor
> > (which doesn't have this restriction) via the adaptor/port number as
> > shown by xvinfo.
> Thanks for this info!  Attached is the output of xvinfo when external
> monitor is plugged in.

Monitor hotplugging doesn't change what's shown by xvinfo.

> It appears that both overlay and textured video are supported, though
> overlay is listed first.  (on my EeePC900 with an intel chipset,
> textured is listed first)

The radeon driver should probably switch the order as well, so most apps
will use the textured adaptor by default.

> I note that VLC allows me to turn off video overlay support entirely
> (Tools > Preferences > Video > "Accelerated video output (Overlay)".
> Unchecking that box lets me render the video on both monitors concurrently.
> I don't see how to do the same thing in totem, though.
> Hm, actually, when i *re-checked* that box in vlc i can still play the
> video on both screens somehow.

VLC can't exceed the hardware limitations. If it plays the video on both
outputs, it's not using the overlay adaptor.

Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer

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