On Wednesday, September 10, 2014 02:09:07 PM Keith Packard wrote:
> Here are a couple of small bug fixes which make DRI3/Present work
> better with UXA.
> 
>  [PATCH 1/2] Do not clear pending kernel events on mode switch
> 
> This patch prevents GL-based compositing managers from wedging when
> performing video mode setting. The problem was that DIX was never
> receiving notification about page flips being completed when one was
> pending across a mode switch.
> 
>  [PATCH 2/2] Correct BO allocation alignment
> 
> This patch makes UXA and Mesa agree about how buffers are allocated
> for images. Without this, UXA was requiring larger padding, which
> meant that converting some textures into pixmaps using DRI3 would
> fail.
> 
> -keith
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Both are:
Tested-by: Kenneth Graunke <kenneth@whitecape.org>

I tested them using DRI3/Present + UXA and DRI3/Present + Glamor on Haswell GT3e.
1. Plug external 2560x1440 DisplayPort monitor into laptop.
2. echo 'exec startkde' > ~/.xinitrc
3. startx
4. xrandr --output DP1 --auto

This used to result in DP1 switching to 2560x1440, but KWin getting stuck waiting on a buffer idle event that never came, so you'd only see a 1920x1080 screen in the top left corner of the display, with either black or white bars in the other area.  Other than the mouse cursor, nothing worked.

With these patches, X works as expected.  Thanks for the fixes, Keith!