On Thu, 4 Oct 2012, Sébastien Dinot wrote: > Alan Stern a écrit : > > The log file shows lots and lots of low-level communication errors. > > They could be caused by bad cabling or by bad USB hardware in your > > computer. It's unlikely that they were caused by the mouse or > > keyboard, because the log shows errors for both of them starting at > > exactly the same times. > > In my humble opinion, this issue is not caused by a bad USB hardware > because I am encountering it with two different motherboards (MSI > Z77A-G43 and ASUS P8Z77-V LX), both with an uptodate BIOS. Maybe they have something in common. I don't know. All I can do is explain to you what your kernel log indicates -- and it strongly indicates a hardware error. Didn't you notice all those "detected XactErr" lines in the log? There were more than 70000 of them! > May be it is caused by a bad cabling but my mouse and my keyboard worked > fine with my previous PC. They are connected to USB2 ports in both > cases. But to clear up this point, I will try new mouse and keyboard. > > A last question: if it is a cable failure, why does it disappear > temporarily when I unload then reload the module? I do not have deep > experience and knowledge of hardware, may be there is a rational > explanation to it. That's a good point, and a cable failure indeed seems less likely than some of the other possibilities (such as a failure of the internal "rate-matching" hub). One possible explanation is that an occasional noisy signal (caused by a slightly faulty cable) triggers a bug in the internal hub, and that bug causes all communication to fail until the hub is reset when you reload the module. > > You could try getting a USB-2 hub and attaching your mouse and > > keyboard through the hub. That might help ... or it might not. > > Sorry, I do not understand the aim of this operation. Could you explain > me it? In addition to what Sarah said, it's possible that your problem is related to the fact that the keyboard and mouse operate at low speed. If you connected them through a hub then that hub would communicate with the internal hub at high speed, not low speed. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
