Hi,
I (Dafna Hirschfeld) will work in following months with Helen Koike to fix the issues
in the TODO file of this driver: drivers/staging/media/rkisp1/TODO
On 15.08.19 15:17, Sakari Ailus wrote:
On Thu, Aug 15, 2019 at 11:24:22AM +0300, Sakari Ailus wrote:
Hi Helen,
On Wed, Aug 14, 2019 at 09:58:05PM -0300, Helen Koike wrote:
...
+static int rkisp1_isp_sd_set_fmt(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ struct v4l2_subdev_format *fmt)
+{
+ struct rkisp1_device *isp_dev = sd_to_isp_dev(sd);
+ struct rkisp1_isp_subdev *isp_sd = &isp_dev->isp_sdev;
+ struct v4l2_mbus_framefmt *mf = &fmt->format;
+
Note that for sub-device nodes, the driver is itself responsible for
serialising the access to its data structures.
But looking at subdev_do_ioctl_lock(), it seems that it serializes the
ioctl calls for subdevs, no? Or I'm misunderstanding something (which is
most probably) ?
Good question. I had missed this change --- subdev_do_ioctl_lock() is
relatively new. But setting that lock is still not possible as the struct
'the struct' - do you mean the 'vdev' struct allocated in
'v4l2_device_register_subdev_nodes' ?
is allocated in the framework and the device is registered before the
driver gets hold of it. It's a good idea to provide the same serialisation
for subdevs as well.
I'll get back to this later.
The main reason is actually that these ops are also called through the
sub-device kAPI, not only through the uAPI, and the locks are only taken
through the calls via uAPI.
actually it seems that although 'subdev_do_ioctl_lock' exit, I wonder if
any subdevice uses that vdev->lock in subdev_do_ioctl_lock.
It is not initialized in v4l2_device_register_subdev_nodes where the vdev is allocated
and I wonder if any subdevice actually initialize it somewhere else. For example it is null in this
driver and in vimc.
So adding the locks to uAPI calls alone would not address the issue.
What I can do is add a mutex to every struct of a subdevice and lock it
at the beginning of each subdevice operation.
Is this an acceptable solution?
Thanks,
Dafna
