Hi Hans, On Wednesday 25 March 2009 11:18:31 Hans de Goede wrote: > <take 2 this time to the new list, hoping it gets some more attention> > > Hi, > > Today it came to my attention (through a libv4l bugreport) that > the uvc driver and the gspca driver handle the setting of > the v4l parent for usb webcams differently. > > The probe function for an usb driver gets passed in a > "struct usb_interface *intf" parameter. > > uvc sets parent to: > > vdev->parent = &intf->dev; > > gspca uses: > struct usb_device *dev = interface_to_usbdev(intf); > vdev.parent = &dev->dev; > > Looking at what for example the usb mass-storage driver > does (with my multi function printer/scanner with cardreader), > which matches UVC, and thinking about how this is supposed to > work with multifunction devices in general, I believe the uvc > driver behaviour is correct, but before writing a patch for > gspca, I thought it would be good to first discuss this on the > list. > > So what do you think ? I obviously agree with you :-) USB class drivers bind to interfaces instead of devices to support composite (multifunction) devices. While drivers for vendor-specific USB devices can bind to the device, in which case the parent could be a USB device, we need to have some consistency in the sysfs symlinks. Using a USB interface as the video device parent regardless of the device type makes sense. Best regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
