Glamor bug in XVideo / XvPutImage when src_y != 0

[Hans de Goede]

Hi Eric,

While working on getting tvtime to work on cards using
the modesetting driver + glamor, I have hit what I believe
is a bug in glamor's XVideo implementation. I've tried
with the current xserver master and it seems the bug is
still present there.

The problem is that src_y seems to get added to dest_y
resulting in the bottom of the window where the tv
is displaying via xv showing garbage when tvtime is
using XvPutImage / XvShmPutImag to put only part of
the tv image on the screen (to get rid of overscan or
show a 16:9 show properly while it is transmitted as 4:3)

Besides the bottom showing garbage the top of the
actual desired content is missing, so src_x does seem
to get correctly applied to the source image, as said
it seems as if it is also getting added to dest_x
(which is 0) shifting the desired image up in the window,
and (correctly) clipping the top of the image of.

Using tvtime requires an old analog tvcard + patches
which I've in my personal git to get it work with
planar yuv XVideo (until now it only supported
packed yuv).

I do not know of another way to reproduce this, but if
you can spot the problem and send me a patch on top of
current xserver master I will happily test it.

Regards,

Hans