On Fri, Jun 3, 2011 at 4:37 AM, Alan Cox alan@lxorguk.ukuu.org.uk wrote:

I have GEM allocation working on the GMA 500 and I can scribble in a framebuffer (minus an odd 'last page' bug which is an off by one somewhere I imagine) and display it with nice modetest stripes.

If I kill the program however it all goes kerblam

drm_release calls into fb_release which duely destroys the user frame buffer. This drops the gem object reference and we start to release all the resources but it blows up because the GEM object is still pinned in the GTT as it's still being used as scanout.

Where I'm a bit lost right now is understanding what is supposed to happen at this point, and how the scanout is supposed to have ended up cleaned up and reset to the system frame buffer beforehand thus unpinning the scanout from the GTT.

I think the intel driver forces a reset to the system scanout on release. I've actually never found a test to indicate it was completely necessary on other GPUs since they scan out of real VRAM which isn't going to get unbound from the card.

Dave.