On Wed, 4 Jul 2012, Frederik Himpe wrote: > > What happens if you disable USB runtime suspend on the affected system? > > Windows tends not to use it. > > It appears to make a difference, but it still does not work perfectly. > > I disabled autosuspend like this: > root@piranha:/sys# for i in $(find -name autosuspend); do echo 0 > $i; done 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. > Then I started usbmon, connected the camera, and tried different times > to run mplayer. All failed again: > http://artipc10.vub.ac.be/~frederik/webcam/usb2-no-autosupend.mon.out This failed for the same reason as before: The webcam autosuspended. > I stopped usbmon. I Tried again starting mplayer, and then 1 in 2 cases, > I got a working image now. However, after a few seconds, the image > starts to lag, stutter and freeze, just like it cannot keep up with the > image from the camera. > > I started usbmon again, and made a trace of this image freezing > happening after a few seconds: > http://artipc10.vub.ac.be/~frederik/webcam/usb2-no-autosupend.mon.out2 This log also has an autosuspend failure. In addition, it shows the image freezing because of a Set-Interface request that was sent while the program was running. I have no idea why that request was sent. > I also don't know whether this is related, but when it's connected to > the usb3 port, the Cheese webcam application tends to freeze when > starting a recording. kernel logs contain these errors when it's > connected to USB3: > [ 1970.959798] usb 3-2: new high-speed USB device number 3 using xhci_hcd > [ 1971.244188] usb 3-2: New USB device found, idVendor=046d, idProduct=0826 > [ 1971.244198] usb 3-2: New USB device strings: Mfr=0, Product=2, SerialNumber=1 > [ 1971.244202] usb 3-2: Product: HD Webcam C525 > [ 1971.244205] usb 3-2: SerialNumber: 1E83E9D0 > [ 1971.511718] uvcvideo: Found UVC 1.00 device HD Webcam C525 (046d:0826) > [ 1971.524373] input: HD Webcam C525 as /devices/pci0000:00/0000:00:14.0/usb3/3-2/3-2:1.2/input/input68 > [ 1971.524608] xhci_hcd 0000:00:14.0: WARN Event TRB for slot 2 ep 14 with no TDs queued? > [ 1971.524617] xhci_hcd 0000:00:14.0: WARN Event TRB for slot 2 ep 0 with no TDs queued? ... An unrelated problem, I think. > But at least mplayer works fine when it's connected to USB3. Alan Stern -- 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
