On Sat, 20 Nov 2010, Robert Pearce wrote: > I don't know if this is the right place to ask, but it seems to be > where the experts are. > > I have a prototype board with an FT4232 on it. Mostly it's working > fine, but if I leave the PC talking to it (or a device connected to it) > for a significant time, I sometimes come back to find the link has > died. Indeed the tty device my software was using no longer exists, and > the FT4232 has been "bumped" around it. > > (This is kernel 2.6.35.7 with a patch to recognise the device PID) > > I've figured out that the USB side is glitching and the kernel is > re-registering the device, leaving out the tty that's already open > because it's not available. The question is why is it glitching? ... > Now, I should probably say that the "Oxford Vacuum Science" > "PicoSphere" (the device with the FT4232) is plugged into a front panel > USB socket on a card reader, This isn't clear. Do you mean that you've got a USB port built into a card reader's front panel and the PicoSphere is plugged into that port? In that case, how is the card reader connected to the computer? > which I suspect means there's a hub in > there. And the big blob of usb-storage stuff makes me wonder whether > it's actually the card reader that's flaky. No, there's no hub. The log shows that the high-speed USB host controller connected to both the PicoSphere and the storage device (the card reader?) stopped working. > My next step will be to try it on a different USB socket, once I can > clear enough space to re-route the 4-metre USB cable I need for that. > The only thing is that the fault doesn't happen often or predictably, > so it'll take some time to satisfy myself that way. I guess I'm hoping > someone here can look at that syslog and say "yeah, those in-Win card > readers fail like that" or "no, that's not what you think" or something. This is not a failure of a peripheral USB device; it's a failure of a controller in the computer. An "lspci" listing might be useful, together with an "lsusb -v" listing. 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
