On Tue, Sep 13, 2016 at 10:38:57AM -0300, Paulo Zanoni wrote: > Ever since I started working on FBC I was already aware that FBC can > really amplify the FIFO underrun symptoms. On systems where FIFO > underruns were harmless error messages, enabling FBC would cause the > underruns to give black screens. > > We recently tried to enable FBC on Haswell and got reports of a system > that would hang after some hours of uptime, and the first bad commit > was the one that enabled FBC. We also observed that this system had > FIFO underrun error messages on its dmesg. Although we don't have any > evidence that fixing the underruns would solve the bug and make FBC > work properly on this machine, IMHO it's better if we minimize the > amount of possible problems by just giving up FBC whenever we detect > an underrun. > > v2: New version, different implementation and commit message. > v3: Clarify the fact that we run from an IRQ handler (Chris). > v4: Also add the underrun_detected check at can_choose() to avoid > misleading dmesg messages (DK). > v5: Fix Engrish, use READ_ONCE on the unlocked read (Chris). > > Cc: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx> > Cc: Lyude <cpaul@xxxxxxxxxx> > Cc: stevenhoneyman@xxxxxxxxx <stevenhoneyman@xxxxxxxxx> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> Looks like it does what you describe, so Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
