drm/i915/gen4: Fix interrupt setup ordering

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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>

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Adam Jackson 2010-05-27 17:26:45 -04:00 • committed by Eric Anholt

parent f458823b86

commit c496fa1fff

1 changed files with 23 additions and 27 deletions

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drivers/gpu/drm/i915/i915_irq.c

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