On Fri, Oct 28, 2011 at 08:59:04AM +0200, Michel Dänzer wrote:
On Don, 2011-10-27 at 22:19 -0500, Ilija Hadzic wrote:
On Thu, 27 Oct 2011, Daniel Vetter wrote:
So I think the right thing to do is
- Kill dev->last_vblank_wait (in a prep patch).
Agreed. Also drm_vblank_info function can go away
Actually, I was rather going to submit a patch to hook it up again — AFAICT it was unhooked without any justification. It could be useful for debugging vblank related hangs. Any issues with it, such as last_vblank_wait not being guaranteed to really be the last one, can always be improved later on.
I've thought a bit about the usefulness of it for debugging before proposing to kill it and I think it can die: It's only really useful for a complete hangs, if we have an issue we just missing a wakeup somewhere, that's not gonna catch things. Hence I think something that allows you to watch things while it's running is much better, i.e. either a drm debug prinkt or a tracecall.
But if you're firmly attached to that debug file it should be pretty easy to shove that under the protection of one of the vblank spinlocks. -Daniel