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