Revert "drm/i915: Avoid waking the engines just to check if they are idle"
authorChris Wilson <chris@chris-wilson.co.uk>
Wed, 27 Feb 2019 20:46:53 +0000 (20:46 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 28 Feb 2019 09:16:38 +0000 (09:16 +0000)
This reverts commit 0b702dca26580e3bbfbbaf22dfc29280b6263414.

CI reports that this is not as reliable as it first appears, with
failures starting to sporadically occur in selftests.

Fixes: 0b702dca2658 ("drm/i915: Avoid waking the engines just to check if they are idle")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190227204654.14907-1-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/intel_engine_cs.c

index 43ce4c5c56c9ee07ee4d881bc821916f1a1041dd..ef49b1b0537b26f9b6e90cb8f53d1544752657d6 100644 (file)
@@ -1007,7 +1007,6 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;
        intel_wakeref_t wakeref;
-       unsigned long flags;
        bool idle = true;
 
        if (I915_SELFTEST_ONLY(!engine->mmio_base))
@@ -1018,19 +1017,15 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
        if (!wakeref)
                return true;
 
-       spin_lock_irqsave(&dev_priv->uncore.lock, flags);
+       /* First check that no commands are left in the ring */
+       if ((I915_READ_HEAD(engine) & HEAD_ADDR) !=
+           (I915_READ_TAIL(engine) & TAIL_ADDR))
+               idle = false;
 
-       /*
-        * Check that no commands are left in the ring.
-        *
-        * If the engine is not awake, both reads return 0 as we do so without
-        * forcewake.
-        */
-       if ((I915_READ_FW(RING_HEAD(engine->mmio_base)) & HEAD_ADDR) !=
-           (I915_READ_FW(RING_TAIL(engine->mmio_base)) & TAIL_ADDR))
+       /* No bit for gen2, so assume the CS parser is idle */
+       if (INTEL_GEN(dev_priv) > 2 && !(I915_READ_MODE(engine) & MODE_IDLE))
                idle = false;
 
-       spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
        intel_runtime_pm_put(dev_priv, wakeref);
 
        return idle;