drm/radeon: add locking around atombios scratch space usage
While developing MST support I noticed I often got the wrong data
back from a transaction, in a racy fashion. I noticed the scratch
space wasn't locked against concurrent users.
Based on a patch by Alex, but I've made it a bit more obvious when
things are locked.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 95d5d4a..11ba9d2 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -100,6 +100,7 @@
memset(&args, 0, sizeof(args));
mutex_lock(&chan->mutex);
+ mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
base = (unsigned char *)(rdev->mode_info.atom_context->scratch + 1);
@@ -113,7 +114,7 @@
if (ASIC_IS_DCE4(rdev))
args.v2.ucHPD_ID = chan->rec.hpd;
- atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+ atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
*ack = args.v1.ucReplyStatus;
@@ -147,6 +148,7 @@
r = recv_bytes;
done:
+ mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
mutex_unlock(&chan->mutex);
return r;