[Intel-gfx] [PATCH 1/6] drm/i915: don't schedule force_wake_timer at gen6_read

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

So far force_wake_timer was only used by gen6_gt_force_wake_put. Since
we always had balanced gen6_gt_force_wake_get/put calls, we could
guarantee balanced calls to intel_runtime_pm_get/put.

Commit 8232644ccf099548710843e97360a3fcd6d28e04, "drm/i915: Convert
the forcewake worker into a timer func" started scheduling the
force_wake_timer at gen6_read, which resulted in an unbalanced
runtime_pm refcount.

So this commit just reverts to the old behavior until we can find a
proper way to used delayed force_wake from the register read/write
macros without leaving the runtime_pm refcounts unbalanced and without
runtime suspending the driver while forcewake is active.

Testcase: igt/pm_pc8
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/intel_uncore.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 7861d97..c91c0c2 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -504,11 +504,12 @@ gen6_read##x(struct drm_i915_private *dev_priv, off_t reg, bool trace) { \
 	    NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
 		dev_priv->uncore.funcs.force_wake_get(dev_priv, \
 						      FORCEWAKE_ALL); \
-		dev_priv->uncore.forcewake_count++; \
-		mod_timer_pinned(&dev_priv->uncore.force_wake_timer, \
-				 jiffies + 1); \
+		val = __raw_i915_read##x(dev_priv, reg); \
+		dev_priv->uncore.funcs.force_wake_put(dev_priv, \
+						      FORCEWAKE_ALL); \
+	} else { \
+		val = __raw_i915_read##x(dev_priv, reg); \
 	} \
-	val = __raw_i915_read##x(dev_priv, reg); \
 	REG_READ_FOOTER; \
 }
 
-- 
1.8.5.3