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

[Ashutosh Dixit]

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.di...@intel.com>
---
 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