drm/amdgpu: fix mec queue policy on single MEC asics

Fixes hangs on single MEC asics.

Fixes: 2ed286fb434 (drm/amdgpu: new queue policy, take first 2 queues of each pipe v2)
Reviewed-by: Alex Xie <AlexBin.Xie@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c

@@ -2825,9 +2825,15 @@ static void gfx_v7_0_compute_queue_acquire(struct amdgpu_device *adev)
 		if (mec >= adev->gfx.mec.num_mec)
 			break;
 
+		if (adev->gfx.mec.num_mec > 1) {
 			/* policy: amdgpu owns the first two queues of the first MEC */
 			if (mec == 0 && queue < 2)
 				set_bit(i, adev->gfx.mec.queue_bitmap);
+		} else {
+			/* policy: amdgpu owns all queues in the first pipe */
+			if (mec == 0 && pipe == 0)
+				set_bit(i, adev->gfx.mec.queue_bitmap);
+		}
 	}
 
 	/* update the number of active compute rings */

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

@@ -1464,9 +1464,15 @@ static void gfx_v8_0_compute_queue_acquire(struct amdgpu_device *adev)
 		if (mec >= adev->gfx.mec.num_mec)
 			break;
 
+		if (adev->gfx.mec.num_mec > 1) {
 			/* policy: amdgpu owns the first two queues of the first MEC */
 			if (mec == 0 && queue < 2)
 				set_bit(i, adev->gfx.mec.queue_bitmap);
+		} else {
+			/* policy: amdgpu owns all queues in the first pipe */
+			if (mec == 0 && pipe == 0)
+				set_bit(i, adev->gfx.mec.queue_bitmap);
+		}
 	}
 
 	/* update the number of active compute rings */

drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c

@@ -873,9 +873,15 @@ static void gfx_v9_0_compute_queue_acquire(struct amdgpu_device *adev)
 		if (mec >= adev->gfx.mec.num_mec)
 			break;
 
+		if (adev->gfx.mec.num_mec > 1) {
 			/* policy: amdgpu owns the first two queues of the first MEC */
 			if (mec == 0 && queue < 2)
 				set_bit(i, adev->gfx.mec.queue_bitmap);
+		} else {
+			/* policy: amdgpu owns all queues in the first pipe */
+			if (mec == 0 && pipe == 0)
+				set_bit(i, adev->gfx.mec.queue_bitmap);
+		}
 	}
 
 	/* update the number of active compute rings */