On Wed, 2 May 2012, Martin Mokrejs wrote: > Alan Stern wrote: > > On Mon, 30 Apr 2012, Grzegorz Nosek wrote: > > > >> W dniu 30.04.2012 23:12, Alan Stern pisze: > >>> 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). > >> > >> Oh. Thanks for the info. Is there a way to force the device into 12Mb/s > >> mode? I don't care about performance as the bottleneck is my Internet > >> link on the client, anyway. The retry logic rendered the console > >> unusable (not just slow, completely no keyboard or redirected media). > > > > In fact there _is_ a way to do it: > > > > echo 7 >/sys/bus/pci/devices/0000:00:1d.7/companion > > > > Here 7 is the number of the port which you want to force to full speed > > and 0000:00:1d.7 is the PCI address of the EHCI controller. > > BTW, when I have a USB3 device detected at high-speed only, how can force it > to super-speed? What filename should I write the echo value? You can't. This mechanism only works for EHCI controllers with a companion UHCI or OHCI controller, so it only allows you to force a high-speed device to connect at full speed. 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
