Overlay issues

[Simon Ser]

On Tuesday, December 15th, 2020 at 5:09 AM, Cornij, Nikola <Nikola.Cornij at amd.com> wrote:

> [AMD Public Use]
>
> Hi Simon,
>
> Just to keep you updated, I've reproduced issue '[1] - Overlay plane:
> position not updated when CRTC_X is negative' on Ubuntu using IGT.
> Seems to happen only with smaller FBs (so far tried 24x24 and I can
> repro, but 300x300 is OK).
>
> I'll look into fixing this.

Thanks for the update and for looking into this! Let me know if I can
help with anything. Nicholas replied on the issue tracker that overlay
planes couldn't have negative positions, so I was thinking of having a
look at the SRC_Y handling (see if we can do the same for SRC_X),
experimenting with FB sizes and SRC_W/H to figure out what's the
overlay max size still triggering the bug. If we really can't emulate
neg SRC_X we should fail atomic commits with negative SRC_X by
returning EINVAL (so that user-space can fall back to not using the
plane in this case).

Simon