Messages in this thread | | | Subject | Re: [PATCH 1/1] V4L: stk11xx, add a new webcam driver | From | Mauro Carvalho Chehab <> | Date | Mon, 04 Jun 2007 15:55:04 -0300 |
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Em Sáb, 2007-06-02 às 11:00 +0200, Thierry Merle escreveu: > > 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. Yes, there's a risk.
> Nevertheless, I will start to specify the framework. > The helper daemon would link to the v4l2-apps/lib.
Ok, thanks! -- Cheers, Mauro
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