[PATCH] drm/amdgpu: fix reload KMD hang on GFX10 KIQ

[Monk Liu]

GFX10 KIQ will hang if we try below steps:
modprobe amdgpu
rmmod amdgpu
modprobe amdgpu sched_hw_submission=4

Due to KIQ is always living there even after KMD unloaded
thus when doing the realod KIQ will crash upon its register
being programed by different values with the previous loading
(the config like HQD addr, ring size, is easily changed if we alter
the sched_hw_submission)

the fix is we must inactive KIQ first before touching any
of its registgers

Signed-off-by: Monk Liu <Monk.Liu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
index 622f442..0702c94 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
@@ -6435,6 +6435,10 @@ static int gfx_v10_0_kiq_init_register(struct amdgpu_ring *ring)
 	struct v10_compute_mqd *mqd = ring->mqd_ptr;
 	int j;
 
+	/* inactivate the queue */
+	if (amdgpu_sriov_vf(adev))
+		WREG32_SOC15(GC, 0, mmCP_HQD_ACTIVE, 0);
+
 	/* disable wptr polling */
 	WREG32_FIELD15(GC, 0, CP_PQ_WPTR_POLL_CNTL, EN, 0);
 
-- 
2.7.4