To semi-answer my own question, I was able to make progress by doing a
modprobe -r ehci-hcd
I now get 4 channels in. It seems like it's not an ALSA or audio problem at all but rather a bug using USB 1.1 devices with ehci-hcd.
I am trying to use an MAudio Quattro with Fedora Core 5 PPC build
2.6.16. I followed the directions here:
but when trying to actually use the Quattro with either jackd or
arecord, I get a dmesg error
cannot submit datapipe for urb 0, err = -28
I get the same error whether I ask for 4 channels or 2. The error -28
is usb bandwidth, but CONFIG_USB_BANDWIDTH was not set, so I'm not
sure what would be causing it to fail. What is going wrong?