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Not sure why the compositor would need to be actively involved. Well first of all I'm not sure if we can reprogram the HW even if all information are available. Please keep in mind that we are in a dma_fence timeout handler here with the usual rat tail of consequences. So no allocation of memory or taking locks under which memory is allocated or are part of preparing the page flip etc... I'm not so deep in the atomic code, so Alex, Sima and probably you as well can answer that much better than I do, but of hand it sounds questionable. On the other hand we could of course postpone reprogramming the CRTC into an async work item, but that might created more problems then it solves. Then second even if the kernel can do it I'm not sure if it should do it. I mean userspace asked for a quick page flip and not some expensive CRTC/PLL reprogramming. Stuff like that usually takes some time and by then the frame which should be displayed by the page flip might already be stale and it would be better to tell userspace that we couldn't display it on time and wait for a new frame to be generated. And third, there must be a root cause of the page flip not completing. My educated guess is that we have some atomic property change or even turning the CRTC off in parallel with the page flip. I mean HW rarely turns off its reoccurring vblank interrupt on its own. Returning an error to userspace might actually help identify the root cause. Regards, Christian.