Hi Adam, On Monday 23 July 2012 16:26:16 Adam Wozniak wrote: > I'm trying to control the "recording" light on a Logitech C270 webcam > from a linux userspace app. > > There is a windows app that does this, so I know it is possible. > > Running the app in a VM, and looking at usbmon output, the following > lines get printed when I turn the light on and off: > > ffff8802adc33c80 1951017902 S Co:1:004:0 s 21 01 0900 0700 0005 5 = > 01010000 0a > ffff8802adc33c80 1952527826 S Co:1:004:0 s 21 01 0900 0700 0005 5 = > 01000000 0a > > so I know this is a "control output" message with "setup" values > bmRequestType=21, bRequest=01, wValue=0900, wIndex=0700, wLength=0005 > and data of 01,0N,00,00,0a where N=1 for on and N=0 for off > > How would I send this same packet from a userspace application? Short answer: don't :-) The right way to control the LED is to map it as a V4L2 control, and then use any V4L2 utility to modify the control value. The uvcvideo driver supports creating UVC -> V4L2 control mappings at runtime. You will need the uvcdynctrl tool and the Logitech control mapping XML description file. The uvcdynctrl package for your distribution should include both, as well as a udev rule to create mappings automatically when the camera is plugged in. -- Regards, Laurent Pinchart -- 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
