Mika Kuoppala 078595043b drm/i915: Don't do posting reads on getting forcewake ... The checking for ack and also any subsequent mmio access will serialize with setting the forcewake bit. Drop the posting read as superfluous. Note that in the put side we still want to keep the posting read as it will ensure that the hw sees our forcewake release in a timely manner and doesn't keep the hw powered up. Comment from Chris: On Wed, Jan 28, 2015 at 05:54:14PM +0200, Mika Kuoppala wrote: > Ville Syrjälä <ville.syrjala@linux.intel.com> writes: > > IIRC the posting read from same cache line actually fixed real bugs. So > > I'm a bit worried about dropping them. But I suppose it's possible only > > the _put side was important for those bugs. > > I found these: > > commit 6af2d180f8 > Author: Daniel Vetter <daniel.vetter@ffwll.ch> > Date: Thu Jul 26 16:24:50 2012 +0200 > > drm/i915: fix forcewake related hangs on snb > > commit 8dee3eea3c > Author: Ben Widawsky <ben@bwidawsk.net> > Date: Sat Sep 1 22:59:50 2012 -0700 > > drm/i915: Never read FORCEWAKE > > https://bugs.freedesktop.org/show_bug.cgi?id=51738 > https://bugs.freedesktop.org/show_bug.cgi?id=52424 > > The snb here seems to survive gem_dummy_reloc_loop and > gem_ring_sync_loop in here with the get side posting removed. Note that we kept the once associated with #52424, but judging by my comments in #51738 the posting read is just a band aid anyway as a full mb() itself was not adequate. Suggested-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> [danvet: paste relevant review discussion in.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>		2015-01-30 17:16:51 +01:00
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drm	drm/i915: Don't do posting reads on getting forcewake	2015-01-30 17:16:51 +01:00
host1x	gpu: host1x: mipi: Set MIPI_CAL_BIAS_PAD_CFG1 register	2014-11-13 16:11:57 +01:00
ipu-v3	gpu: ipu-di: Switch to DIV_ROUND_CLOSEST for DI clock divider calc	2015-01-07 19:15:04 +01:00
vga	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-10-13 16:23:15 +02:00
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