On Fri, 22 Oct 2010, Daniel Stöckner wrote: > Hello, > > On Sun, 25 Jul 2010, Sam Gentle wrote: > > > When I attempt to record from it, I get "ALSA start: broken pipe" and > > this error in my dmesg: "cannot submit datapipe for urb 0, error -28: > > not enough bandwidth" > > I have a similar problem with a 4-in/2-out USB soundcard called Lexicon > Omega. Using Ubuntu Maverick, I wrote to the Ubuntu Forums > ( http://ubuntuforums.org/showthread.php?t=1603137 ) and they told me > to ask alsa-devel list, which wrote that this problem is USB related. > > When using the device as 2-in/2-out it works fine, but when trying > to get 4-in, bandwidth message appears and audio I/O stops. > > When using the device in simplex mode, it works as expected, but it is > necessary for me, to have duplex with 4/2. I am using kernel 2.6.35 > and alsa 1.0.23 (both Ubuntu shipped). The kernel is configured with > CONFIG_USB_EHCI_TT_NEWSCHED=y > > The soundcard is connected directly to the notebook, however, there > are internal USB devices: a webcam and a fingerprint sensor. > > output of lsusb without soundcard: > Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub > Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 001 Device 004: ID 04f2:b130 Chicony Electronics Co., Ltd > Bus 001 Device 003: ID 08ff:168b AuthenTec, Inc. > Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Alan Stern suggested the following: > > > For now, your best bet may be to force the built-in hub to connect at > > full speed instead of high speed. You can do this by writing the hub's > > port number to the "companion" file in the EHCI controller's sysfs > > directory. For example, in your "connect" log the hub was attached to > > port 6 on bus 1, so you could do: > > > > echo 6 >/sys/bus/usb/devices/usb1/../companion > > I tried that, but with "1" and "2", as the hub is device 1 and 2 on Bus 2, > but it did not work (hub just stopped working). The output of lsusb -v > is attached (before fiddling with companion). Is there anything else > I can post here or try on my system? Any hint is greatly appreciated! Have you tried unloading the webcam driver? It may not make any difference, but avoiding potential interference between devices is always a good idea. If that doesn't work, build a kernel with CONFIG_DEBUG_FS and CONFIG_USB_DEBUG enabled. Mount a debugfs filesystem on /sys/kernel/debug. Then while running a test, make copies of the files under /sys/kernel/debug/usb/ehci/B, where B is the appropriate directory for the bus your soundcard is plugged into. 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
