Re: [RFCv1 PATCH 1/7] gspca: allow subdrivers to use the control framework.

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 05/05/2012 04:44 PM, Hans de Goede wrote:
> Hi,
>
> On 05/05/2012 11:14 AM, Hans Verkuil wrote:
>> So you get:
>>
>> vidioc_foo()
>> lock(mylock)
>> v4l2_ctrl_s_ctrl(ctrl, val)
>> s_ctrl(ctrl, val)
>> lock(mylock)
>
> Easy solution here, remove the first lock(mylock), since we are not using v4l2-dev's
> locking, we are the one doing the first lock, and if we are going to call v4l2_ctrl_s_ctrl
> we should simply not do that!
>
> Now I see that we are doing exactly that in for example vidioc_g_jpegcomp in gspca.c, so
> we should stop doing that. We can make vidioc_g/s_jpegcomp only do the usb locking if
> gspca_dev->vdev.ctrl_handler == NULL, and once all sub drivers are converted simply remove
> it. Actually I'm thinking about making the jpegqual control part of the gspca_dev struct
> itself and move all handling of vidioc_g/s_jpegcomp out of the sub drivers and into
> the core.

Here is an updated version of this patch implementing this approach for
vidioc_g/s_jpegcomp. We may need to do something similar in other places, although I cannot
think of any such places atm,

Regards,

Hans