On Fri, May 15, 2009 at 8:46 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > The problem described in that thread appears to be a genuine bug. In > short, ehci-hcd doesn't do a clear-TT-buffer when a low/full-speed > async URB is unlinked. When that happens the buffer remains busy > indefinitely, and when all the buffers are busy the hub won't work > right. > > This patch may fix the problem. I haven't tested it, so you guys will > have to be the guinea pigs. :-) Wow! This discussion got very technical very fast. Let me see if I---a relatively USB-naive user---have this right. My DUB-7 hub may have an ISP1521 chip that shares a single TT among all 7 ports. This fact may trigger a bug in the Linux USB driver when low or full speed devices are plugged into the hub. However, since all of my devices are high-speed USB 2.0 devices (sorry I forgot to mention that in my original post), this bug and your patch are unfortunately irrelevant to my problem. Alan: I'll try the troubleshooting steps you recommended---testing the hub with a different cable, computer, and OS---and let you know how I fare. Thanks to everyone for your help so far. --Ethan -- 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
