[PATCH 3/3] drm/i915/hwmon: Block waiting for GuC reset to complete

[Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>]

Instead of erroring out when GuC reset is in progress, block waiting for
GuC reset to complete which is a more reasonable uapi behavior.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_hwmon.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 9ab8971679fe3..4343efb48e61b 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -51,6 +51,7 @@ struct hwm_drvdata {
 	char name[12];
 	int gt_n;
 	bool reset_in_progress;
+	wait_queue_head_t wqh;
 };
 
 struct i915_hwmon {
@@ -400,10 +401,15 @@ hwm_power_max_write(struct hwm_drvdata *ddat, long val)
 	int ret = 0;
 	u32 nval;
 
+retry:
 	mutex_lock(&hwmon->hwmon_lock);
 	if (hwmon->ddat.reset_in_progress) {
-		ret = -EAGAIN;
-		goto unlock;
+		mutex_unlock(&hwmon->hwmon_lock);
+		ret = wait_event_interruptible(ddat->wqh,
+					       !hwmon->ddat.reset_in_progress);
+		if (ret)
+			return ret;
+		goto retry;
 	}
 	wakeref = intel_runtime_pm_get(ddat->uncore->rpm);
 
@@ -426,7 +432,6 @@ hwm_power_max_write(struct hwm_drvdata *ddat, long val)
 			 PKG_PWR_LIM_1_EN | PKG_PWR_LIM_1, nval);
 exit:
 	intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
-unlock:
 	mutex_unlock(&hwmon->hwmon_lock);
 	return ret;
 }
@@ -508,6 +513,7 @@ void i915_hwmon_power_max_restore(struct drm_i915_private *i915, bool old)
 	intel_uncore_rmw(hwmon->ddat.uncore, hwmon->rg.pkg_rapl_limit,
 			 PKG_PWR_LIM_1_EN, old ? PKG_PWR_LIM_1_EN : 0);
 	hwmon->ddat.reset_in_progress = false;
+	wake_up_all(&hwmon->ddat.wqh);
 
 	mutex_unlock(&hwmon->hwmon_lock);
 }
@@ -784,6 +790,7 @@ void i915_hwmon_register(struct drm_i915_private *i915)
 	ddat->uncore = &i915->uncore;
 	snprintf(ddat->name, sizeof(ddat->name), "i915");
 	ddat->gt_n = -1;
+	init_waitqueue_head(&ddat->wqh);
 
 	for_each_gt(gt, i915, i) {
 		ddat_gt = hwmon->ddat_gt + i;
-- 
2.38.0