On Tue, 26 Oct 2010, Daniel Stöckner wrote: > This is very strange. How should 4+2 mode then be possible? Tried > kernels 2.6.31 up to 2.6.36 (64 bit for this machine) and the problem > always remains the same. > > However on another (older) machine with 32 bit kernel 2.6.31, it works > like a charm in 4+2 44100 24bit! Double-checked it; the audio really > goes through. 4-track recording and simultaneous 2-track playback works > perfectly. lsusb -v of the working 32 bit machine and the not working 64 > bit machine is attached, maybe it helps... If necessary I can recompile > the kernel on the working machine with usb debugging. Sure, go ahead and try it. At the same time, make sure that CONFIG_USB_MON is enabled and try collecting a usbmon trace showing the a few seconds of the test. Instructions are in the kernel source file Documentation/usb/usbmon.txt. > I saw that on the old machine, there is a 1.1 hub explicitly listed, > beside the 2.0 hubs. On the new (not working) machine, there are only > 2.0 hubs. That's probably the reason for the difference. On the old machine the sound card will connect to a UHCI controller instead of an EHCI controller. Which means you'll have to copy a different file to get the debugging information: /sys/kernel/debug/usb/uhci/0000:00:1d.0 (if you plug the card into the same USB port as before). One copy will be enough. Also, before running the test you should do: echo 2 >/sys/module/uhci_hcd/parameters/debug 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
