On Wed, 2012-07-04 at 21:20 -0400, Alan Stern wrote: > On Wed, 4 Jul 2012, Frederik Himpe wrote: > > > > That doesn't disable autosuspend. The proper way is: > > > > > > echo on >/sys/bus/usb/devices/.../power/control > > > > > > where you fill in the "..." with the directory name for the webcam. > > > > usb trace from trying mplayer a few times after disabling autosuspend: > > > > ffff880415761ec0 897158138 S Ii:1:081:7 -115:128 16 < > > ffff8803c49ec800 897158252 S Co:1:081:0 s 21 01 0100 0003 001a 26 = 01000101 15160500 00000000 00000000 00000000 00000000 0000 > > ffff8803c49ec800 897162252 C Co:1:081:0 -71 0 > > This is already too late. The -71 error code indicates that the webcam > has crashed. We need to see what happens before the crash, in order to > determine what causes it. > > Did you use the right path for the webcam device? According to your > logs, it should be 1-1.2 -- assuming you plug the webcam into the same > port as before. OK, new attempt. I plug in webcam: Jul 5 21:19:02 piranha kernel: [ 9611.555849] usb 1-1.2: new high-speed USB device number 5 using ehci_hcd Jul 5 21:19:03 piranha kernel: [ 9611.913815] usb 1-1.2: New USB device found, idVendor=046d, idProduct=0826 Jul 5 21:19:03 piranha kernel: [ 9611.913827] usb 1-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=1 Jul 5 21:19:03 piranha kernel: [ 9611.913832] usb 1-1.2: Product: HD Webcam C525 Jul 5 21:19:03 piranha kernel: [ 9611.913835] usb 1-1.2: SerialNumber: 1E83E9D0 Jul 5 21:19:03 piranha kernel: [ 9612.180813] uvcvideo: Found UVC 1.00 device HD Webcam C525 (046d:0826) Jul 5 21:19:03 piranha kernel: [ 9612.193342] input: HD Webcam C525 as /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/1-1.2:1.2/input/input27 I run: # cat /sys/bus/usb/devices/1-1.2/power/control auto # echo on > /sys/bus/usb/devices/1-1.2/power/control At this moment, the device disconnects and reconnects, according to the logs: Jul 5 21:20:40 piranha kernel: [ 9709.169304] usb 1-1.2: USB disconnect, device number 5 Jul 5 21:20:40 piranha kernel: [ 9709.416109] usb 1-1.2: new high-speed USB device number 6 using ehci_hcd Jul 5 21:20:41 piranha kernel: [ 9709.774203] usb 1-1.2: New USB device found, idVendor=046d, idProduct=0826 Jul 5 21:20:41 piranha kernel: [ 9709.774215] usb 1-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=1 Jul 5 21:20:41 piranha kernel: [ 9709.774219] usb 1-1.2: Product: HD Webcam C525 Jul 5 21:20:41 piranha kernel: [ 9709.774222] usb 1-1.2: SerialNumber: 1E83E9D0 Jul 5 21:20:41 piranha kernel: [ 9710.040969] uvcvideo: Found UVC 1.00 device HD Webcam C525 (046d:0826) Jul 5 21:20:41 piranha kernel: [ 9710.053472] input: HD Webcam C525 as /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/1-1.2:1.2/input/input28 And it's back to auto: # cat /sys/bus/usb/devices/1-1.2/power/control auto I tried setting to on again, and then this appears in the logs: Jul 5 21:21:59 piranha kernel: [ 9788.223118] usb 1-1.2: USB disconnect, device number 6 Jul 5 21:22:00 piranha kernel: [ 9788.330415] usb 1-1.2: new full-speed USB device number 7 using ehci_hcd Jul 5 21:22:00 piranha kernel: [ 9788.402207] usb 1-1.2: device descriptor read/64, error -32 Jul 5 21:22:00 piranha kernel: [ 9788.577706] usb 1-1.2: device descriptor read/64, error -32 Jul 5 21:22:00 piranha kernel: [ 9788.753203] usb 1-1.2: new full-speed USB device number 8 using ehci_hcd Jul 5 21:22:00 piranha kernel: [ 9788.824996] usb 1-1.2: device descriptor read/64, error -32 Jul 5 21:22:00 piranha kernel: [ 9789.000493] usb 1-1.2: device descriptor read/64, error -32 Jul 5 21:22:00 piranha kernel: [ 9789.175991] usb 1-1.2: new full-speed USB device number 9 using ehci_hcd Jul 5 21:22:01 piranha kernel: [ 9789.582701] usb 1-1.2: device not accepting address 9, error -32 Jul 5 21:22:01 piranha kernel: [ 9789.654621] usb 1-1.2: new full-speed USB device number 10 using ehci_hcd Jul 5 21:22:01 piranha kernel: [ 9790.061329] usb 1-1.2: device not accepting address 10, error -32 Jul 5 21:22:01 piranha kernel: [ 9790.061467] hub 1-1:1.0: unable to enumerate USB device on port 2 I reproduced this with usbmon running: http://artipc10.vub.ac.be/~frederik/webcam/usbmon.1u # cat /sys/kernel/debug/usb/usbmon/1u > /tmp/usbmon.1u Plug in webcam # cat /sys/bus/usb/devices/1-1.2/power/control auto # echo on > /sys/bus/usb/devices/1-1.2/power/control [device disconnects and reconnects, according to log] # echo on > /sys/bus/usb/devices/1-1.2/power/control [this time the device disconnects and reconnects again] -- Frederik Himpe <fhimpe@xxxxxxxxxx> -- 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