linux-kernel - [PATCH 2/5] thermal/core: Reset cooling state during cooling device unregistration

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Message-Id: <20230324070807.6342-2-rui.zhang@intel.com>
Date:   Fri, 24 Mar 2023 15:08:04 +0800
From:   Zhang Rui <rui.zhang@...el.com>
To:     linux-pm@...r.kernel.org, rafael.j.wysocki@...el.com,
        daniel.lezcano@...aro.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] thermal/core: Reset cooling state during cooling device unregistration

When unregistering a cooling device, it is possible that the cooling
device has been activated. And once the cooling device is unregistered,
no one will deactivate it anymore.

Reset cooling state during cooling device unregistration.

Signed-off-by: Zhang Rui <rui.zhang@...el.com>
---
In theory, this problem that this patch fixes can be triggered on a
platform with ACPI Active cooling, by
1. overheat the system to trigger ACPI active cooling
2. unload ACPI fan driver
3. check if the fan is still spinning
But I don't have such a system so I didn't trigger then problem and I
only did build & boot test.
---
 drivers/thermal/thermal_core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 30ff39154598..fd54e6c10b60 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1192,6 +1192,10 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
 		}
 	}
 
+	mutex_lock(&cdev->lock);
+	cdev->ops->set_cur_state(cdev, 0);
+	mutex_unlock(&cdev->lock);
+
 	mutex_unlock(&thermal_list_lock);
 
 	device_unregister(&cdev->device);
-- 
2.25.1