Re: [PATCH 1/1] V4L: stk11xx, add a new webcam driver

[Thierry Merle <thierry.merle@free.fr>]

Mauro Carvalho Chehab a écrit :
> > > This seems to be an interesting approach.
> > >
> > >   
> > >       
> > Interesting but impossible to do for ioctl calls.
> > When the application does a ioctl(fd_of_mnt_video0,VIDIOC_G_FMT,&arg) 
> > for example, there is no way for the userspace helper to catch this ioctl.
> > The application could only open/read from the userspace helper's file 
> > /mnt/video0.
> > ioctl would still have to be done on the kernel device driver.
> > I thought also about a /proc interface for decompression algorithms (a 
> > helper would listen on a /proc file and write on another /proc file) but 
> > /proc is not designed for that kind of thing.
> > A separate library seems to be the simplest solution.
> >     
>
> There are some ways for this to work. For example, you may create a
> helper device for the daemon driver to bind, even requiring it to have
> root permission.
>
>   
Right, but I am afraid that complex userspace/kernelspace context 
changes breaks performance.
Nevertheless, I will start to specify the framework.
The helper daemon would link to the v4l2-apps/lib.
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