xf86-video-intel: unexpected phenomenon on XV texture adapter with no scaling

[Krzysztof Halasa]

Hi,

"Jacques, Hugo" <Hugo.Jacques at verint.com> writes:

> I get a strange phenomenon using the XV texture adapter in YV12 format
> on my 945G hardware and a 2.7.0 xf86-video-intel driver.
>
> I fill a rectangle with many 1 pixel-high horizontal lines. Odd lines
> are black and even lines are white.  I send this rectangle using
> XVShmPutImage to a window with the same size so that no scaling
> occurs.
>
> I would expect to see the black/white horizontal lines pattern. But I
> get a uniformly grey rectangle!

I think we're then in some sort of Matrix. I just opened the xorg list
folder to write about precisely the same observation :-)

> Same phenomenon appears on either VGA,
> DVI or CVBS-TV monitors: it doesn't seem to be monitor/video encoder
> issue-related.

Yes. BTW the data in video memory is already "corrupted" - tested with
mplayer, playdv for simplicity, and verified with xwd.

The same on i915 + git driver and on Radeon RV6xx with Fedora 11. The
effects are precisely the same, there is some averaging/filtering here.
But it only happens with Xvideo output - X11 and GL are fine. OTOH on
R300 it's different - textured XVideo output looks good (at least much
better, that's a high res display and individual pixels are hard to
see), but the XVideo overlay has the symptom (RV6xx has no overlay).

I'm trying to implement that long-forgotten i830+ interlaced mode for
video display and thought at first it's caused by interlaced flag. It
is precisely the same in progressive mode as well.

I remember I saw a similar effect on i915 with overlay. Can't seem to
get the overlay to work now, though.

If not this, it seems I could have a good video playback without using
the fb driver at last.


Perhaps someone has an idea where to start searching for this? Must be
some offset, as experiment with scaling can show.
-- 
Krzysztof Halasa