On Mon, 20 Dec 2010, Piotr Isajew wrote: > On Mon, Dec 20, 2010 at 03:15:05PM -0500, Alan Stern wrote: > > On Mon, 20 Dec 2010, Piotr Isajew wrote: > > > > > Hello, > > > > > > I would like to get back to this. I've been testing hso with > > > debugging turned on. From what I see, there are sometimes > > > problems with result detaching devices from the bus. From > > > application point of view, at the beginning there is an IO > > > timeout, and then device disappears. Current tests show that > > > device reattaches in a while, application can reopen it and > > > continue it's job. > > > > Your log shows that you are getting lots of hardware communication > > errors. You should check the quality of your USB cables and > > connectors. > > > That could be the point, but it's the system with several modems > connected through 2 external USB hubs. Nobody touches it. After > device reattaches, it works fine for several hours if not days > (no XactErrs then). Before I started to use those hubs I worked > with 3 other from different vendor and there have been similar > symptoms. I would rather bet there is something wrong with Option > modems in general, that makes them irresponsible to the OS under > some circumstances. Or maybe there's something wrong with the USB components in your computer. Or something in your environment causing electromagnetic noise in the USB cables (bad fluorescent lights, for example). > The question is: can this situation be > handled without disconnecting the device (ie. by increasing > number of retries)? I have no idea. You can try increasing the number of retries (up to 255): QH_XACTERR_MAX in drivers/usb/host/ehci.h. 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
