On Tue, Sep 02, 2014 at 05:31:22PM +0300, Ville Syrjälä wrote: > On Tue, Sep 02, 2014 at 02:57:36PM +0100, Chris Wilson wrote: > > Long ago, back in the racy haydays of 915gm interrupt handling, page > > flips would occasionally go astray and leave the hardware stuck, and the > > display not updating. This annoyed people who relied on their systems > > being able to display continuously updating information 24/7, and so > > some code to detect when the driver missed the page flip completion > > signal was added. Until recently, it was presumed that the interrupt > > handling was now flawless, but once again Simon Farnsworth has found a > > system whose display will stall. Reinstate the pageflip stall detection, > > which works by checking to see if the hardware has been updated to the > > new framebuffer address following each vblank. If the hardware is > > scanning out from the new framebuffer, but we still think the flip is > > pending, then we kick our driver into submision. > > > > This is a continuation of the effort started with > > commit 4e5359cd053bfb7d8dabe4a63624a5726848ffbc > > Author: Simon Farnsworth <simon.farnsworth@xxxxxxxxxxxx> > > Date: Wed Sep 1 17:47:52 2010 +0100 > > > > drm/i915: Avoid pageflipping freeze when we miss the flip prepare interrupt > > > > This now includes a belt-and-braces approach to make sure the driver > > (or the hardware) doesn't miss an interrupt and cause us to stop > > updating the display should the unthinkable happen and the pageflip fail - i.e. > > that the user is able to continue submitting flips. > > I have this plan that we stop using the flip done interrupts, > since they're anyway fairly broken on bdw. But I haven't really > thought how that would interact with this stall checking. Now that you remind me, I had a plan to rewrite this on top of that future. > But I guess we can merge this stuff first and figure out the rest > when someone gets around to posting a patch for killing flip done. Yeah, I think this is important in the short term as we have a bug causing system freezes that this at least (+ next patch) allows us to recover from. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
