[PATCH 1/3] media: wave5: Fix PM runtime usage count underflow
From: Xulin Sun
Date: Tue Dec 02 2025 - 23:11:27 EST
Symptom:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 963 at kernel/kthread.c:1430 kthread_destroy_worker+0x84/0x98
...
vdec 30210000.video-codec: Runtime PM usage count underflow!
Root cause:
The driver calls pm_runtime_put_sync() unconditionally in remove, but
the device may already be suspended due to autosuspend configured in
probe. When autosuspend has already suspended the device, the usage
count is 0, and pm_runtime_put_sync() decrements it to -1, causing
the underflow warning.
Fix:
Replace pm_runtime_put_sync() with pm_runtime_dont_use_autosuspend()
which properly pairs with pm_runtime_use_autosuspend() from probe.
This allows pm_runtime_disable() to handle reference count cleanup
correctly regardless of current suspend state. The disable function
internally handles the usage count properly without causing underflow.
Signed-off-by: Xulin Sun <xulin.sun@xxxxxxxxxxxxx>
---
drivers/media/platform/chips-media/wave5/wave5-vpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu.c b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
index e1715d3f43b0..23aa3ab51a0e 100644
--- a/drivers/media/platform/chips-media/wave5/wave5-vpu.c
+++ b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
@@ -356,7 +356,7 @@ static void wave5_vpu_remove(struct platform_device *pdev)
hrtimer_cancel(&dev->hrtimer);
}
- pm_runtime_put_sync(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
pm_runtime_disable(&pdev->dev);
mutex_destroy(&dev->dev_lock);
--
2.49.1