From: Martin Kepplinger <martin.kepplinger@puri.sm>
To: laurent.pinchart@ideasonboard.com
Cc: kernel@puri.sm, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, martin.kepplinger@puri.sm,
mchehab@kernel.org, sakari.ailus@iki.fi
Subject: [PATCH v2] media: hi846: fix usage of pm_runtime_get_if_in_use()
Date: Tue, 25 Apr 2023 11:47:47 +0200 [thread overview]
Message-ID: <20230425094747.2769693-1-martin.kepplinger@puri.sm> (raw)
pm_runtime_get_if_in_use() does not only return nonzero values when
the device is in use, it can return a negative errno too.
And especially during resuming from system suspend, when runtime pm
is not yet up again, -EAGAIN is being returned, so the subsequent
pm_runtime_put() call results in a refcount underflow.
Fix system-resume by handling -EAGAIN of pm_runtime_get_if_in_use().
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
---
revision history
----------------
v2 (thank you Sakari and Laurent):
* drop the other patch (the streaming-state in suspend/resume needs to
be solved differently).
* Sakari pointed out that many drivers are affected by this and that
runtime-pm might need changes instead. I think this patch doesn't hurt
and could serve as a reminder to do so.
v1: initial submission:
https://lore.kernel.org/linux-media/20230405092904.1129395-1-martin.kepplinger@puri.sm/
drivers/media/i2c/hi846.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/media/i2c/hi846.c b/drivers/media/i2c/hi846.c
index 306dc35e925f..f8709cdf28b3 100644
--- a/drivers/media/i2c/hi846.c
+++ b/drivers/media/i2c/hi846.c
@@ -1353,7 +1353,8 @@ static int hi846_set_ctrl(struct v4l2_ctrl *ctrl)
exposure_max);
}
- if (!pm_runtime_get_if_in_use(&client->dev))
+ ret = pm_runtime_get_if_in_use(&client->dev);
+ if (!ret || ret == -EAGAIN)
return 0;
switch (ctrl->id) {
--
2.30.2
next reply other threads:[~2023-04-25 9:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-25 9:47 Martin Kepplinger [this message]
2023-05-16 13:22 ` [PATCH v2] media: hi846: fix usage of pm_runtime_get_if_in_use() Sakari Ailus
2023-05-23 10:07 ` Martin Kepplinger
2023-05-29 20:40 ` Sakari Ailus
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