drm/radeon: Add a rmb() in IH processing
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>
Wed, 13 Jul 2011 06:28:19 +0000 (16:28 +1000)
committerDave Airlie <airlied@redhat.com>
Mon, 25 Jul 2011 11:42:39 +0000 (12:42 +0100)
commit964f664520a4c6a247e2c9ff8b4481631cf746df
tree11bbb5e5f82b7ca236c0d40b76fd11f6efed634d
parentf1bece7fde9820a99c14d4db46ef071000e4ba47
drm/radeon: Add a rmb() in IH processing

We should have a read memory barrier between reading the WPTR from
memory and reading ring entries based on that value (ie, we need to
ensure both loads are done in order by the CPU).

It could be argued that the MMIO reads in r600_ack_irq() might be
enough to get that barrier but I prefer keeping an explicit one just
in case.

[airlied: fix evergreen + r/w mixup]

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drivers/gpu/drm/radeon/evergreen.c
drivers/gpu/drm/radeon/r600.c