Hardware+driver difference (intel vs. ati)

[Alex Deucher]

On 5/30/07, Gilles Dartiguelongue <dartigug at esiee.fr> wrote:
> Hi list,
>
> I have both a i830 and a r200 powered laptop.
>
> When playing a video with xv, the i830 powered laptop shows the video on
> both screens while the r200 doesn't. Is it because of a difference in
> the driver or because the i830 chipset has just one CRTC with 2 physical
> outputs or something like that ?

probably the i830 is driving two outputs with one crtc.  by default
the radeon driver drives each output with it's own crtc.  Both chips
only have one overlay and it can only be used on one crtc at a time.

>
> Bonus question, with the radeon driver, is it possible to switch
> on-the-fly the screen used by xv ? The use case behind this question is
> a presentation of video encoding stuff (artifacts, sharpness, ...).
>

Both can be controlled via Xv attributes (use an app like xvattr to
change the settings).  On intel is it XV_PIPE, on radeon it is
XV_SWITCHCRT.  use xvinfo to see the current settings.

Alex