Is there something I could look for in the usbmon dump to track down what is causing this? I'd really like to figure out if there is a way around this limitation (or what is limiting the system) without dividing the problem among multiple machines in order to conquer it. This is an 8 core machine with 32 Gb of RAM and a huge number of USB controllers, it seems nuts that it can't record 12, 640x480 video streams at once.... -jason ----- Original Message ----- From: "Alan Stern" <stern@xxxxxxxxxxxxxxxxxxx> To: "Jason N Pitt" <jpitt@xxxxxxxxx> Cc: "USB list" <linux-usb@xxxxxxxxxxxxxxx> Sent: Thursday, September 22, 2011 7:22:15 AM Subject: Re: uvcvideo: Failed to resubmit video URB (-27) On Wed, 21 Sep 2011, Pitt, Jason N wrote: > +From: "Alan Stern" <stern@xxxxxxxxxxxxxxxxxxx > > +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. > > What aspect of the system would I be overwhelming? The PCI bus bandwidth, the CPU, ... I don't know what else. > > 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. > > Too large or too far into the future for what? For the driver and the controller hardware to handle. > +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. > > What information could I provide? To begin with, the "lsusb -v" output for one of the webcams. Are they all the same? Let's also see a usbmon log. Follow the instructions in Documentation/usb/usbmon.txt. Since you're tracing events on multiple USB buses, you'll have to use the 0u file. It will help if you first unplug as many USB devices as possible that aren't directly involved in the test. Alan Stern -- /* Jason Pitt PhD 206.667.5603 Roth Lab jpitt@xxxxxxxxx Basic Sciences Division Fred Hutchinson Cancer Research Center 1100 Fairview Ave N A3-135 Seattle, WA 98109 */ -- 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
