[PATCH v2 1/1] drm/i915: Hold RPM reference while setting freq limits through sysfs

[Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx>]

This changes ensures device is active when frequency limits are changed.
This is needed as we are writing to register RPNSWREQ in intel_set_rps.
If not done, might lead to undesired errors like:
[ 1965.189137] [drm:fw_domains_get] *ERROR* blitter: timed out waiting for forcewake ack to clear.

v2: Added elaborate commit message. (Jani)
    Fixing RPM reference drop in early exit paths. (Ville)

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_sysfs.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index c6188dd..2d576b7 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -370,6 +370,8 @@ static ssize_t gt_max_freq_mhz_store(struct device *kdev,
 
 	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
 
+	intel_runtime_pm_get(dev_priv);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 
 	val = intel_freq_opcode(dev_priv, val);
@@ -378,6 +380,7 @@ static ssize_t gt_max_freq_mhz_store(struct device *kdev,
 	    val > dev_priv->rps.max_freq ||
 	    val < dev_priv->rps.min_freq_softlimit) {
 		mutex_unlock(&dev_priv->rps.hw_lock);
+		intel_runtime_pm_put(dev_priv);
 		return -EINVAL;
 	}
 
@@ -398,6 +401,8 @@ static ssize_t gt_max_freq_mhz_store(struct device *kdev,
 
 	mutex_unlock(&dev_priv->rps.hw_lock);
 
+	intel_runtime_pm_put(dev_priv);
+
 	return count;
 }
 
@@ -433,6 +438,8 @@ static ssize_t gt_min_freq_mhz_store(struct device *kdev,
 
 	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
 
+	intel_runtime_pm_get(dev_priv);
+
 	mutex_lock(&dev_priv->rps.hw_lock);
 
 	val = intel_freq_opcode(dev_priv, val);
@@ -441,6 +448,7 @@ static ssize_t gt_min_freq_mhz_store(struct device *kdev,
 	    val > dev_priv->rps.max_freq ||
 	    val > dev_priv->rps.max_freq_softlimit) {
 		mutex_unlock(&dev_priv->rps.hw_lock);
+		intel_runtime_pm_put(dev_priv);
 		return -EINVAL;
 	}
 
@@ -457,6 +465,8 @@ static ssize_t gt_min_freq_mhz_store(struct device *kdev,
 
 	mutex_unlock(&dev_priv->rps.hw_lock);
 
+	intel_runtime_pm_put(dev_priv);
+
 	return count;
 
 }
-- 
1.9.1

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