[PATCH 1/8] drm/i915: Rebalance runtime pm vs forcewake

Mika Kuoppala
2014-12-08T18:24:18Z

From: Chris Wilson <chris@chris-wilson.co.uk>

Calling intel_runtime_pm_put() is illegal from a soft-irq context, so
revert the crude hack

commit aa0b3b5bb8768c1a6a6788869d9c7015eae7e80c
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Tue Apr 1 14:55:07 2014 -0300

drm/i915: don't schedule force_wake_timer at gen6_read

and apply the single line corrective instead.

References: https://bugs.freedesktop.org/show_bug.cgi?id=80913
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_drv.c | 1 +
drivers/gpu/drm/i915/intel_uncore.c | 18 ++++++------------
2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 71be3c9..706b122 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1402,6 +1402,7 @@ static int intel_runtime_suspend(struct device *device)
}

del_timer_sync(&dev_priv->gpu_error.hangcheck_timer);
+ intel_uncore_forcewake_reset(dev, false);
dev_priv->pm.suspended = true;

/*
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 46de8d7..38ac389 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -449,8 +449,6 @@ static void gen6_force_wake_timer(unsigned long arg)
if (--dev_priv->uncore.forcewake_count == 0)
dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
-
- intel_runtime_pm_put(dev_priv);
}

void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
@@ -586,7 +584,6 @@ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)
void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
{
unsigned long irqflags;
- bool delayed = false;

if (!dev_priv->uncore.funcs.force_wake_put)
return;
@@ -603,21 +600,19 @@ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
goto out;
}

-
spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
WARN_ON(!dev_priv->uncore.forcewake_count);

if (--dev_priv->uncore.forcewake_count == 0) {
dev_priv->uncore.forcewake_count++;
- delayed = true;
mod_timer_pinned(&dev_priv->uncore.force_wake_timer,
jiffies + 1);
}
+
spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);

out:
- if (!delayed)
- intel_runtime_pm_put(dev_priv);
+ intel_runtime_pm_put(dev_priv);
}

void assert_force_wake_inactive(struct drm_i915_private *dev_priv)
@@ -777,12 +772,11 @@ 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); \
- 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); \
+ dev_priv->uncore.forcewake_count++; \
+ mod_timer_pinned(&dev_priv->uncore.force_wake_timer, \
+ jiffies + 1); \
} \
+ val = __raw_i915_read##x(dev_priv, reg); \
hsw_unclaimed_reg_debug(dev_priv, reg, true, false); \
REG_READ_FOOTER; \
}
--
1.9.1