plug the VRAM leak in radeon driver

[Alex Deucher]

Applied.  thanks!

Alex

On Sat, Nov 2, 2013 at 11:00 PM, Ilija Hadzic <ilijahadzic at gmail.com> wrote:
> The following patches will plug the VRAM leak that can be provoked in the
> radeon driver by changing the mode. The mechanism that causes the leak is
> described in the commit message associated with the first patch.
>
> The way I have caused it (and tested the fix) was temporarily hack up debug
> counters in radeon_bo_pin and radeon_bo_unpin functions. Then I connected
> two monitor one of which had 1600x1200 for preferred mode, while the other
> had preferred mode of the other monitor was 1280x720. Then I repetitively
> unplugged and plugged back the 1600x1200 monitor and ran 'xrandr --auto'
> between each plug/unplug operation. Without the fix, the number of pinned
> buffers grew at each plug/unplug operation. With the fix, the counter
> remained stable throughout the test.
>
> Note that I only effectively tested the first patch, because I don't have any
> GPUs that are old enough to use the legacy CRTC path in the driver. Still,
> based on my findings for AtomBIOS GPUs, I believe that the second patch
> is correct and necessary.
>
> regards,
>
> Ilija
>
>