[PATCH] drm/i915/gvt: grab runtime pm first for forcewake use

[Xiaolin Zhang]

in workload_thread, it should grab runtime pm wakelock and later
uncore forcewake get will check rpm wakelock held successfully.
otherwise, sometimes, rpm wakelock not hold and print call trace below:

 Call Trace:
  intel_uncore_forcewake_get+0x15/0x20 [i915]
  workload_thread+0x5f9/0x16f0 [i915]
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70
  ? __switch_to_asm+0x34/0x70
  ? __switch_to+0x85/0x3f0
  ? __switch_to_asm+0x40/0x70
  ? do_wait_intr_irq+0x90/0x90
  kthread+0x121/0x140
  ? intel_vgpu_clean_workloads+0x100/0x100 [i915]
  ? kthread_park+0x90/0x90
  ret_from_fork+0x35/0x40
 --[ end trace 86525f742a02e12c ]--

Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
---
 drivers/gpu/drm/i915/gvt/scheduler.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index a1580df..7cfcaf5 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -1012,6 +1012,8 @@ static int workload_thread(void *priv)
 				workload->ring_id, workload,
 				workload->vgpu->id);
 
+		intel_runtime_pm_get(gvt->dev_priv);
+
 		gvt_dbg_sched("ring id %d will dispatch workload %p\n",
 				workload->ring_id, workload);
 
@@ -1041,6 +1043,7 @@ static int workload_thread(void *priv)
 			intel_uncore_forcewake_put(&gvt->dev_priv->uncore,
 					FORCEWAKE_ALL);
 
+		intel_runtime_pm_put_unchecked(gvt->dev_priv);
 		if (ret && (vgpu_is_vm_unhealthy(ret)))
 			enter_failsafe_mode(vgpu, GVT_FAILSAFE_GUEST_ERR);
 	}
-- 
1.8.3.1