On Tue, Jun 11, 2013 at 3:57 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote: > On Tue, Jun 11, 2013 at 03:49:27PM -0700, St?phane Marchesin wrote: >> During suspend all fences are reset, including their pin_count which >> is reset to 0. However a framebuffer can be bound across >> suspend/resume, which means that when the buffer is unbound after >> resume, the pin count for the buffer will be negative. Since the >> fence pin count is now negative when available and zero when in use, >> the buffer's fence will get recycled when the fence is in use which >> is the opposite of what we want. The visible effect is that since the >> fence is recycled the tiling mode goes away while the buffer is being >> displayed and we get lines/screens of garbage. >> >> To fix this, we repin the fences for all bound fbs on resume, which >> ensures the pin count is right. > > Yikes. So why do we not just keep the fences alive during suspend (not > touching their pin_count), and then just iterate over the list of fences > rewriting the register as required upon resume? That would seem less > error prone than trying to reconstruct the lost pin_count. I suspect they'd need to be saved/restored at the hw level as well, which AFAICS isn't happening today... St?phane
