tree bbdc1b56f61f12d68509a2f927a9c777dc35eee7
parent f458823b864c6def488f951a79986fa205aba4f1
author Adam Jackson <ajax@redhat.com> 1274995605 -0400
committer Eric Anholt <eric@anholt.net> 1275697301 -0700

drm/i915/gen4: Fix interrupt setup ordering

Unmask, then enable interrupts, then enable interrupt sources; matches
PCH ordering.  The old way (sources, enable, unmask) gives a window
during which interrupt conditions would appear in ISR but would never
reach IIR and thus never raise an IRQ.  Since interrupts only trigger
on rising edges in ISR, this would lead to conditions where (for
example) output hotplugging would never fire an interrupt because it
was already stuck on in ISR.

Also, since we know IIR and PIPExSTAT have been cleared during
irq_preinstall, don't clear them again during irq_postinstall, nothing
good can come of that.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>