On Thu, 22 Mar 2012 15:00:50 +0000, Chris Wilson <chris at chris-wilson.co.uk> wrote: > Quoting the BSpec from time immemorial: > > PIPEACONF, bits 28:27: Frame Start Delay (Debug) > > Used to delay the frame start signal that is sent to the display planes. > Care must be taken to insure that there are enough lines during VBLANK > to support this setting. > > An instance of the BIOS leaving these bits set was found in the wild, > where it caused our modesetting to go all squiffy and skewiff. > > References: https://bugs.freedesktop.org/show_bug.cgi?id=47271 > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk> > Cc: stable at kernel.org Reported-and-tested-by: Carl Richell <carl at system76.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43012 -Chris -- Chris Wilson, Intel Open Source Technology Centre
