On Sun, 29 Apr 2012, Grzegorz Nosek wrote: > W dniu 19.04.2012 19:40, Alan Stern pisze: > > Do you have any idea what's going wrong? > > Nope. I found this workaround by bisecting. > > > Can you provide complete dmesg logs for kernels both with and without > > your patch (and with CONFIG_USB_DEBUG enabled)? Maybe also usbmon > > traces too. > > Attached. Sorry it took so long, it was rather hard to align time when I > can easily reboot this machine with when I actually had the time to do it. > > Note: USB support is compiled in the kernel image, so I couldn't attach > usbmon very early. Instead, I captured usbmon traces (and dmesgs since > boot) from connecting and disconnecting an ISO image via the KVM's > virtual CD drive, which exhibits the same problems (the IPKVM is visible > as an USB keyboard, an USB mouse and two USB CD-ROM drives). That's fine; the logs show pretty clearly what the problem is. It isn't a software issue. You've got a hardware problem; either the IPKVM itself, or the connecting cable, or your computer's EHCI controller is bad. The only reason the device worked without the retry logic is because it failed so completely that the kernel was forced to run it at full speed (12 Mb/s) instead of high speed (480 Mb/s). With the retry logic present, the device was barely workable at high speed (but it probably didn't work well enough to be very useful). Have you tried plugging the IPKVM into a different computer to see if it behaves any better? 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
