drm/amdgpu/gfx8: reset compute ring wptr on the GPU on resume

Commit 42cdf6f ("drm/amdgpu/gfx8: always restore kcq MQDs") made the
ring pointer always to be reset on resume from suspend. This caused compute
rings to fail since the reset was done without also resetting it for the
firmware. Reset wptr on the GPU to avoid a disconnect between the driver
and firmware wptr.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3911
Fixes: 42cdf6f ("drm/amdgpu/gfx8: always restore kcq MQDs")
Signed-off-by: Eeli Haapalainen <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit 2becafc)
Cc: [email protected]

Author: eemikh

drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c

@@ -4640,6 +4640,7 @@ static int gfx_v8_0_kcq_init_queue(struct amdgpu_ring *ring)
 			memcpy(mqd, adev->gfx.mec.mqd_backup[mqd_idx], sizeof(struct vi_mqd_allocation));
 		/* reset ring buffer */
 		ring->wptr = 0;
+		atomic64_set((atomic64_t *)ring->wptr_cpu_addr, 0);
 		amdgpu_ring_clear_ring(ring);
 	}
 	return 0;