On Thu May 22 16:35:10 2025 +0200, Mathis Foerst wrote:
> Getting / Setting the frame interval using the V4L2 subdev pad ops
> get_frame_interval/set_frame_interval causes a deadlock, as the
> subdev state is locked in the [1] but also in the driver itself.
>
> In [2] it's described that the caller is responsible to acquire and
> release the lock in this case. Therefore, acquiring the lock in the
> driver is wrong.
>
> Remove the lock acquisitions/releases from mt9m114_ifp_get_frame_interval()
> and mt9m114_ifp_set_frame_interval().
>
> [1] drivers/media/v4l2-core/v4l2-subdev.c - line 1129
> [2] Documentation/driver-api/media/v4l2-subdev.rst
>
> Fixes: 24d756e914fc ("media: i2c: Add driver for onsemi MT9M114 camera
> sensor")
> Cc: [email protected]
> Signed-off-by: Mathis Foerst <[email protected]>
> Reviewed-by: Laurent Pinchart <[email protected]>
> Signed-off-by: Sakari Ailus <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/i2c/mt9m114.c | 8 --------
1 file changed, 8 deletions(-)
---
diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index 6c80c6926aef..3f540ca40f3c 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -1619,13 +1619,9 @@ static int mt9m114_ifp_get_frame_interval(struct
v4l2_subdev *sd,
if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE)
return -EINVAL;
- mutex_lock(sensor->ifp.hdl.lock);
-
ival->numerator = 1;
ival->denominator = sensor->ifp.frame_rate;
- mutex_unlock(sensor->ifp.hdl.lock);
-
return 0;
}
@@ -1644,8 +1640,6 @@ static int mt9m114_ifp_set_frame_interval(struct
v4l2_subdev *sd,
if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE)
return -EINVAL;
- mutex_lock(sensor->ifp.hdl.lock);
-
if (ival->numerator != 0 && ival->denominator != 0)
sensor->ifp.frame_rate = min_t(unsigned int,
ival->denominator /
ival->numerator,
@@ -1659,8 +1653,6 @@ static int mt9m114_ifp_set_frame_interval(struct
v4l2_subdev *sd,
if (sensor->streaming)
ret = mt9m114_set_frame_rate(sensor);
- mutex_unlock(sensor->ifp.hdl.lock);
-
return ret;
}
