drm/i915: Avoid a double-read of PCH_IIR during interrupt handling
commit98cfca8e0d48cd792d830198a34617668b10ed2c
authorChris Wilson <chris@chris-wilson.co.uk>
Wed, 9 May 2012 20:45:43 +0000 (9 21:45 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 1 Jun 2012 07:12:59 +0000 (1 15:12 +0800)
treef809ce96bfb954c5295e6b50d221b950dda16521
parentd818cf47642e6379d61d9304fed3ca7c9d6786a8
drm/i915: Avoid a double-read of PCH_IIR during interrupt handling

commit 9adab8b5a7fde248504f484e197589f3e3c922e2 upstream.

Currently the code re-reads PCH_IIR during the hotplug interrupt
processing. Not only is this a wasted read, but introduces a potential
for handling a spurious interrupt as we then may not clear all the
interrupts processed (since the re-read IIR may contains more interrupts
asserted than we clear using the result of the original read).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/i915/i915_irq.c