On Sunday, September 30, 2012 12:54 AM, Alan Stern wrote:
It's seems pretty clear that these problems are the result of a hardware bug in your OHCI controller. There's no simple way to work around it in the driver. But you can work around it by not attaching the sound card to that controller. Buy a USB-2.0 hub and plug the sound card into it (but don't attach the keyboard or mouse to the hub; leave them plugged directly into the computer).
Ok, cool. I did some further googling about this OHCI issue, and I came across one Gentoo forum thread (too bad I can't find it right now). And they were discussing the same issue: apparently (at least) with the 2.6-series kernels the Geforce 8200 OHCI controller, which is what I have, did not have these issues. (Due to driver workarounds?)
Anyways, I tried plugging the MobilePre through a cheap-o Belkin USB 2.0 hub to my PC. And since that I have been running the Ardour playback more than 15mins!
So apparently the USB 2.0 hub has a "transaction translation" going on, when connecting a USB 1.1 device to it. And due to the translation, the 1.1 device shows up as USB 2.0 (EHCI) device to the OS/driver. Did I get this correctly?
Anyways: thanks a bunch! Now I can finally start to debug the Jack issues with the latencies and stuff - and hopefully eventually I get some tracks laid down... :)
Best regards, -Lassi P.S. Oh, and I will be looking into revising that usbmon.txt at some point.. -- 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
