Messages in this thread | | | Subject | Re: [PATCH v8 05/14] media: rkisp1: add Rockchip ISP1 subdev driver | From | Dafna Hirschfeld <> | Date | Fri, 31 Jan 2020 20:38:34 +0100 |
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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 >
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