i810 driver: Xv on mergefd

Alex Deucher alexdeucher at gmail.com
Sun Aug 27 07:24:30 PDT 2006

On 8/27/06, Erwin Rol <mailinglists at erwinrol.com> wrote:
> On Sun, 2006-08-27 at 12:26 +0200, Rene Rebe wrote:
> > On Sunday 27 August 2006 12:19, Erwin Rol wrote:
> > > Hey all,
> > >
> > > Is it possible to do Xv on a 852GM with mergedfb ? I have it working on
> > > one screen , but on the second screen i only get the blue ColorKey
> > > color.
> >
> > I do not have the SPECs, but it is likely that the chip only has one
> > hardware overlay. The only thing that is doable in that case is an option
> > to force it on the first or second pipe.
> this would not be a problem, because the video has to be full screen on
> screen 1 or full screen on screen 2, not on both at the same time, and
> not half on one and half on the other screen.
> This worked fine on a  M9 radeon, that also has only one overlay, but it
> doesn't seem to work on the i810. I have one LCD panel connected to the
> LVDS output, and one to a VGA output, it works on the LVDS output, but
> on the VGA output it stays blue.
> The VGA/CRT is Pipe A en the LVDS/LFP is Pipe B.

IIRC, the intel hardware has a bit to source the overlay to either
crtc, same as radeon.  On radeon I just wrote a small function to
check which head more of the video was on and then I'd switch the
overlay source bit accordingly.  The function should be easily ported
to intel if it's not already.  See RADEONChooseOverlayCRTC() in


> - Erwin

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