Re: [PULL] http://www.linuxtv.org/hg/~hverkuil/v4l-dvb

[Hans de Goede <j.w.r.degoede@xxxxxx>]

Hans Verkuil wrote:
> Hi Mauro,
> 
> I've added the following change as well:
> 
> - v4l2-dev: use register_chrdev_region and remove video_open.
> 


p.s.

I also wonder how this impacts the patches which add proper reference counting 
of how many times the device is opened and which then do not simply free the 
video_device struct in video_unregister_device, but instead decrement the ref 
count, keeping the video_device struct around, stopping calls to v4l2_ioctl on 
open file handles to a device which has been unregistered from oopsing with a 
null ptr dereference. Which in turn allows usb drivers to simply call 
unregister in usb_disconnect instead of having todo their own reference 
counting and all kind of tricks such as wrapping v4l2_ioctl to check for a 
disconnected (and thus unregistered) device before calling the real v4l2_ioctl.

It would be _really_ nice to have this for gspca, as I'm planning on doing some 
cleanup on gspca locking and disconnect handling. So I wonder what the status 
of the patch for this ref counting are and how this interact with the removal 
of video_opem .


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