[Intel-gfx] [PATCH] drm/i915: Finish enabling rps before use by sysfs or debugfs

[Tom.O'Rourke at intel.com]

From: Tom O'Rourke <Tom.O'Rourke at intel.com>

Enabling rps (turbo setup) was put in a work queue because it may
take quite awhile.  This change flushes the work queue to initialize
rps values before use by sysfs or debugfs.  Specifically,
rps.delayed_resume_work is flushed before using rps.hw_max,
rps.max_delay, rps.min_delay, or rps.cur_delay.

This change fixes a problem in sysfs where show functions using
uninitialized values show incorrect values and store functions
using uninitialized values in range checks incorrectly fail to
store valid input values.  This change also addresses similar use
before initialized problems in debugfs.

Change-Id: Ib9c4f2066b65013094cb9278fc17958a964836e7
Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c |   12 ++++++++++++
 drivers/gpu/drm/i915/i915_sysfs.c   |   10 ++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 1d77624..52e90a1 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -843,6 +843,8 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	int ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	if (IS_GEN5(dev)) {
 		u16 rgvswctl = I915_READ16(MEMSWCTL);
 		u16 rgvstat = I915_READ16(MEMSTAT_ILK);
@@ -1321,6 +1323,8 @@ static int i915_ring_freq_table(struct seq_file *m, void *unused)
 		return 0;
 	}
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
 	if (ret)
 		return ret;
@@ -1972,6 +1976,8 @@ i915_max_freq_get(void *data, u64 *val)
 	if (!(IS_GEN6(dev) || IS_GEN7(dev)))
 		return -ENODEV;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
 	if (ret)
 		return ret;
@@ -1996,6 +2002,8 @@ i915_max_freq_set(void *data, u64 val)
 	if (!(IS_GEN6(dev) || IS_GEN7(dev)))
 		return -ENODEV;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	DRM_DEBUG_DRIVER("Manually setting max freq to %llu\n", val);
 
 	ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
@@ -2034,6 +2042,8 @@ i915_min_freq_get(void *data, u64 *val)
 	if (!(IS_GEN6(dev) || IS_GEN7(dev)))
 		return -ENODEV;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
 	if (ret)
 		return ret;
@@ -2058,6 +2068,8 @@ i915_min_freq_set(void *data, u64 val)
 	if (!(IS_GEN6(dev) || IS_GEN7(dev)))
 		return -ENODEV;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	DRM_DEBUG_DRIVER("Manually setting min freq to %llu\n", val);
 
 	ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index d572435..270892b 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -213,6 +213,8 @@ static ssize_t gt_cur_freq_mhz_show(struct device *kdev,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 	if (IS_VALLEYVIEW(dev_priv->dev)) {
 		u32 freq;
@@ -245,6 +247,8 @@ static ssize_t gt_max_freq_mhz_show(struct device *kdev, struct device_attribute
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 	if (IS_VALLEYVIEW(dev_priv->dev))
 		ret = vlv_gpu_freq(dev_priv->mem_freq, dev_priv->rps.max_delay);
@@ -269,6 +273,8 @@ static ssize_t gt_max_freq_mhz_store(struct device *kdev,
 	if (ret)
 		return ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 
 	if (IS_VALLEYVIEW(dev_priv->dev)) {
@@ -317,6 +323,8 @@ static ssize_t gt_min_freq_mhz_show(struct device *kdev, struct device_attribute
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 	if (IS_VALLEYVIEW(dev_priv->dev))
 		ret = vlv_gpu_freq(dev_priv->mem_freq, dev_priv->rps.min_delay);
@@ -341,6 +349,8 @@ static ssize_t gt_min_freq_mhz_store(struct device *kdev,
 	if (ret)
 		return ret;
 
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 
 	if (IS_VALLEYVIEW(dev)) {
-- 
1.7.9.5