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 <[email protected]>
---
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/[email protected]/
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
Hi Martin,
On Tue, Apr 25, 2023 at 11:47:47AM +0200, Martin Kepplinger wrote:
> 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 <[email protected]>
> ---
>
> 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.
I guess it's appropriate to add:
Fixes: e8c0882685f9 ("media: i2c: add driver for the SK Hynix Hi-846 8M pixel camera")
--
Sakari Ailus
Am Dienstag, dem 16.05.2023 um 16:22 +0300 schrieb Sakari Ailus:
> Hi Martin,
>
> On Tue, Apr 25, 2023 at 11:47:47AM +0200, Martin Kepplinger wrote:
> > 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 <[email protected]>
> > ---
> >
> > 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.
>
> I guess it's appropriate to add:
>
> Fixes: e8c0882685f9 ("media: i2c: add driver for the SK Hynix Hi-846
> 8M pixel camera")
>
I agree. Feel free to do so when applying.
martin
On Tue, May 23, 2023 at 12:07:54PM +0200, Martin Kepplinger wrote:
> Am Dienstag, dem 16.05.2023 um 16:22 +0300 schrieb Sakari Ailus:
> > Hi Martin,
> >
> > On Tue, Apr 25, 2023 at 11:47:47AM +0200, Martin Kepplinger wrote:
> > > 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 <[email protected]>
> > > ---
> > >
> > > 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.
> >
> > I guess it's appropriate to add:
> >
> > Fixes: e8c0882685f9 ("media: i2c: add driver for the SK Hynix Hi-846
> > 8M pixel camera")
> >
>
> I agree. Feel free to do so when applying.
Done!
--
Sakari Ailus