tree 60ac84ef32b7590618bc81b0b52a5ba14a49bf45
parent 42b923b587d055cd98fb84f32e3e758672026ae9
author Dave Airlie <airlied@redhat.com> 1324293329 +0000
committer Dave Airlie <airlied@redhat.com> 1329417067 +0000

drm: move pci bus master enable into driver.

The current enabling of bus mastering in the drm midlayer allows a large
race condition under kexec. When a kexec'ed kernel re-enables bus mastering
for the GPU, previously setup dma blocks may cause writes to random pieces
of memory. On radeon the writeback mechanism can cause these sorts of issues.

This patch doesn't fix the problem, but it moves the bus master enable under
the individual drivers control so they can move enabling it until later in
their load cycle and close the race.

Fix for radeon kms driver will be in a follow-up patch.

Signed-off-by: Dave Airlie <airlied@redhat.com>