On Sun, 7 Aug 2011, Alan Stern wrote: > On Sun, 7 Aug 2011, Adam Baker wrote: > > > I've addec Hans de Geode and linux-usb to the CC as this response picks up on > > a related discussion about the usb mini summit. > > > > On Friday 05 August 2011, Theodore Kilgore wrote: > > > > If you can solve the locking problem between devices in the kernel then > > > > it shouldn't matter if one of the kernel devices is the generic device > > > > that is used to support libusb. > > > > > > Hmmm. Perhaps not. While we are on the topic, what exactly do you mean by > > > "the generic device that is used to support libusb." Which device is that, > > > exactly? > > > > The file drivers/usb/core/devio.c registers itself as a driver called > > usb_device which is used to provide all of the device drivers that live under > > /proc/bus/usb > > Let's get things correct. The driver is called usbfs, not usb_device. > The things that live under /proc/bus/usb are files representing USB > devices, not device drivers. This indirectly answers my question, above, about whatever device there may or may not be. What I get from this, and also from a bit of snooping around, is that there is not any dev that gets created in order to be accessed by libusb. Just an entry under /proc/bus/usb, which AFAICT is at most a pseudo-device. Thanks. So, Alan, what do you think is the best way to go about the problem? The camera can act as a stillcam or as a webcam. The problem is to provide access to both, with equal facility (and of course to lock out access to whichever action is not currently in use, if the other one is). The current situation with libusb does not cut it, as among other things it currently does only half the job and seemingly cannot address the locking problem. Hans suggests to create two explicit devices, /dev/video (as already done and something like /dev/cam. Then access webcam function as now and stillcam function with libgphoto2, as now, but through /dev/cam instead of through libusb. This would seem to me to solve all the problems, but at the expense of some work. Can you think of something more clever? Theodore Kilgore -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
