[PATCH driver/intel] Allow copy_front() to fail and clean up gracefully if it does

[Chris Wilson]

On Wed, Sep 24, 2014 at 12:34:29PM +0200, Egbert Eich wrote:
> Here is the test scenario:
> 
> Pineview Chipset, start a bare X server (without the other patch applied
> to the driver), start xterm on it.
> 
> On my system 'xrandr -q' gives:
> 
> Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
> LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 222mm x 125mm
>    1366x768       60.0*+
>    1024x768       60.0  
>    800x600        60.3     56.2  
>    640x480        59.9  
> VGA1 disconnected (normal left inverted right x axis y axis)
> VIRTUAL1 disconnected (normal left inverted right x axis y axis)
> 
> now run 'xrandr --output LVDS1 --panning 3048x768' (or whatever
> other output it uses).
> 
> For panning one needs to be able to draw into the screen pixmap outside 
> of the area exposed by the crtc.

Note that the screen pixmap still exists and is drawn into by the
clients. What should happen with the panning is that the CRTC is updated
through set_mode_major which invalidates the new CRTC location in the big
screen Pixmap and the contents copied during the next shadow update.

That's the theory at least...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre