From: Xulin Sun <xulin.sun@windriver.com>
To: nas.chung@chipsnmedia.com, jackson.lee@chipsnmedia.com,
mchehab@kernel.org
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
xulin.sun@windriver.com
Subject: [PATCH 1/3] media: wave5: Fix PM runtime usage count underflow
Date: Wed, 3 Dec 2025 12:09:33 +0800 [thread overview]
Message-ID: <20251203040935.2685490-2-xulin.sun@windriver.com> (raw)
In-Reply-To: <20251203040935.2685490-1-xulin.sun@windriver.com>
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@windriver.com>
---
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
next prev parent reply other threads:[~2025-12-03 4:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-03 4:09 [PATCH 0/3] media: wave5: Fix critical issues in driver remove path Xulin Sun
2025-12-03 4:09 ` Xulin Sun [this message]
2025-12-03 4:09 ` [PATCH 2/3] media: wave5: Fix kthread worker destruction in polling mode Xulin Sun
2025-12-03 4:09 ` [PATCH 3/3] media: wave5: Fix device cleanup order to prevent kernel panic Xulin Sun
2025-12-03 18:10 ` [PATCH 0/3] media: wave5: Fix critical issues in driver remove path Nicolas Dufresne
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