'Zaphod' dual-head and mirroring

[Dave Airlie]

On Thu, Jul 8, 2010 at 7:32 AM, Martin Langhoff
<martin.langhoff at gmail.com> wrote:
> Hi list,
>
> I am working with a sisusbvga device, attempting to set it up as a
> mirror of the main display. This is on an XO-1.5, where the main
> display hw, using viafb, only has one video port connected to the
> LVDS.
>
> Is there any way in current X.org to mirror across the two devices?
> (In practice we also need scaling for the external display -- but
> let's consider it optional.)
>
> Is there a way to get a ServerLayout/Screen stanza in xorg.conf that
> handles mirroring in zaphod mode?

Well lets the terminology correct first, this isn't zaphod mode, that
implies 2 heads on one card, what you have is just multi-card.

Now I've no idea if our xinerama implementation can do cloned xinerama
where it sends the same command to both drivers to render the same
scene. Otherwise you'd need to make the usb card read from main memory
where the VIA GPU has its scanout buffer since the VIA is an IGP.  I'd
mention the scanout would have to be linear, but I've no idea if VIA
have even figured out what tiling is yet.

Dave.