On Thu, 31 Jan 2019 13:13:22 +0000 Peter Rosin peda@axentia.se wrote:
On 2019-01-27 09:27, Boris Brezillon wrote:
On Thu, 10 Jan 2019 15:10:28 +0000 Peter Rosin peda@axentia.se wrote:
Hi!
I found an unfortunate issue while recoding plane handling to use drm_atomic_helper_check_plane_state(). The driver rotates clockwise, which is not correct. I simply fixed it (patch 1/4), but maybe that will cause regressions for unsuspecting users who simply assumed that the clockwise rotation was correct? I don't know what to do about that? Adding an option to get the old broken behavior seems useless, wouldn't it be just as easy to just fix whatever app to rotate the other way instead of adding an option somewhere?
I have only tested this series on sama5d3, but I did check the docs for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35 and sam9x35) supported by the driver (relevant to patch 4/4).
Cheers, Peter
Peter Rosin (4): drm/atmel-hlcdc: rotate planes counterclockwise drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated drm/atmel-hlcdc: fix clipping of planes
Queued patches 1-3 to drm-misc-next.
Great, thanks.
drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
Still waiting for Nicolas feedback on this one.
[Adding back Nicolas, he seems to have gone missing from the list recipients.]
I have done some testing of that patch and for me it's a definite improvement. The test I did was removing a white plane from a white background. Without the patch, the driver will output black where the plane was for the current frame (since the driver does that disc-area thing for the largest hidden part of the background). With the patch, I get no visual glitches when removing a plane.
I use a plane to scroll a text, and if you know what to look for, the black rectangle that flickers by as the plane with the scrolling text is removed is little bit disturbing. Not a significant problem, and maybe only geeks notice it, but still...
Just wanted to say that the resulting "black hole" mentioned in the other thread really does exist and that the patch may make sense beyond the fact that it removes usage of undocumented features.
I have not seen any bad side effects fro the patch, but admittedly my testing was very limited and I did not try to remove the plane while doing other stuff with the driver. So, there might still be reasons for removing planes immediately...
Since everything is now synchronized on vsync events thanks to the atomic modeset infra (including plane/crtc disable requests), I think the problem I was trying to fix at the time no longer exists (might re-appear if we start supporting async plane disable requests which is anyway not supported by the core). So I think I'll just apply your patch.
Thanks,
Boris