[PATCH 2/2] drm/amdkfd: Preserve CP_MQD_IQ_RPTR internal state

[Oded Gabbay]

From: Jay Cornwall <jay.cornwall at amd.com>

CP microcode uses undocumented bits in this register to record queue
state information. The KFD zeroes these bits in update_mqd, when invoked
through the UPDATE_QUEUE ioctl, causing incoherent state when the ioctl
is used to successively unmap and map a queue.

Since the queue type cannot be changed in this path, move the MQD write
to init_mqd.

Signed-off-by: Jay Cornwall <jay.cornwall at amd.com>
Reviewed-by: Ben Goz <ben.goz at amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
index a318743..a09e18a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
@@ -94,6 +94,9 @@ static int init_mqd(struct mqd_manager *mm, void **mqd,
 	m->cp_hqd_pipe_priority = 1;
 	m->cp_hqd_queue_priority = 15;
 
+	if (q->format == KFD_QUEUE_FORMAT_AQL)
+		m->cp_hqd_iq_rptr = AQL_ENABLE;
+
 	*mqd = m;
 	if (gart_addr != NULL)
 		*gart_addr = addr;
@@ -187,7 +190,6 @@ static int update_mqd(struct mqd_manager *mm, void *mqd,
 	m->cp_hqd_vmid = q->vmid;
 
 	if (q->format == KFD_QUEUE_FORMAT_AQL) {
-		m->cp_hqd_iq_rptr = AQL_ENABLE;
 		m->cp_hqd_pq_control |= NO_UPDATE_RPTR;
 	}
 
-- 
1.9.1