drm/i915: Don't wake the device up to check if the engine is asleep
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 12 Feb 2018 09:39:28 +0000 (09:39 +0000)
committerRodrigo Vivi <rodrigo.vivi@intel.com>
Tue, 13 Feb 2018 07:35:03 +0000 (23:35 -0800)
If the entire device is powered off, we can safely assume that the
engine is also asleep (and idle).

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: a091d4ee931b ("drm/i915: Hold a wakeref for probing the ring registers")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180212093928.6005-1-chris@chris-wilson.co.uk
(cherry picked from commit 74d00d28a15c8452f65de0a9477b52d95639cc63)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
drivers/gpu/drm/i915/intel_engine_cs.c

index d790bdc..acc661a 100644 (file)
@@ -1458,7 +1458,9 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
        struct drm_i915_private *dev_priv = engine->i915;
        bool idle = true;
 
-       intel_runtime_pm_get(dev_priv);
+       /* If the whole device is asleep, the engine must be idle */
+       if (!intel_runtime_pm_get_if_in_use(dev_priv))
+               return true;
 
        /* First check that no commands are left in the ring */
        if ((I915_READ_HEAD(engine) & HEAD_ADDR) !=