Messages like this should always be posted to the linux-usb mailing list. On Tue, 20 Sep 2011, Pitt, Jason N wrote: > Hi Alan- > > Sorry to bug you, but I saw your response to a similar issue on the > Linux-usb list and you seemed insightful so I thought I'd try > bothering you. I have an ubuntu 11.04 machine that I'm trying to > capture 12 usb webcam microscope feeds on. The webcams are split > over 3 pcie usb cards and the motherboards's usb controller. I'm > encountering instability using both streamer and guvcview. I can get > all 12 streams running but eventually one dies (in a minute or so) > and then about 3 more die as well...leaving me with 7 or 8 stable > streams. From your post it seems as though there is a limitation in > the number of UVC_URBS or a timeout problem with the UVC driver? There are limitations. You may simply be trying to do more than your system can handle. > The guvcview error is: > > Could not grab image (select timeout): Resource temporarily unavailable > > > which is repeated repeatedly.... > > > the streamer error is: > v4l2: oops: select timeouts > > this usually only effects one or two cameras > > > > with both programs dmesg yields: > > [ 5330.048166] uvcvideo: Failed to resubmit video URB (-27). > [ 5330.048174] uvcvideo: Failed to resubmit video URB (-27). > [ 5330.048178] uvcvideo: Failed to resubmit video URB (-27). > [ 5330.048183] uvcvideo: Failed to resubmit video URB (-27). > [ 5330.048188] uvcvideo: Failed to resubmit video URB (-27). > > > Any advice would be greatly appreciated! -27 is EFBIG, which indicates that uvcvideo tried to schedule a transfer that was too large or extended too far into the future. This could be because the driver fell behind the real-time stream and wasn't able to keep up. Without more detailed information it's impossible to tell exactly what's wrong. 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
