On Thu, 13 Dec 2007, Jay Monkman wrote: > I'm trying to use a USB audio device on a MPC8349 (PowerPC SoC) > system. The processor has a built in EHCI controller.
Does it also have a built-in OHCI controller? > I've tried several audio devices and they all behave the same way. The > debug output I'm including was generated while using a Turtle Beach > Amigo. > > My test is running a simple loopback program - an infinite loop that > reads from the capture side and writes to the playback side. I'm using > ALSA, not OSS. > > If I plug the audio device into a hub which is plugged into the system, it > works fine. Does the hub run at full speed or high speed? What about the audio device? > If I plug the audio device into the system directly > (without a hub), it doesn't work. It seems to read and write some > data, but very slowly - it iterates through the read/write loop about > 1/50 as fast as when I use a hub. > > The system I'm trying to use this on doesn't have a hub built in. It > has a single USB port which is connected to a transceiver which is > connected to the CPU. > > I'm running kernel version 2.6.20.11. I tried 2.6.23 but had the same > problem. > > > I don't see anything in dmesg that indicates any real difference > between the two cases. > > I've attached the usbmon output from > inserting the device - no hub > running the loopback test - no hub > inserting the device - with a hub > running the loopback test - with a hub You got them mixed up. The first two attachments show a hub and the last two don't. > I truncated the logs from running the test program to 100 lines. I > can provide more output if that would be helpful. > > Can anyone tell me why this is happening, or even better how to fix > it? Any help is appreciated. The timings in the log for the run without a hub don't make much sense. Something is badly wrong with either the driver or the USB controller hardware. Can you post the contents of /proc/bus/usb/devices for the two cases (with and without hub)? Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
