2010/8/20 Dennis Nezic <dennisn@xxxxxxxxxxxxxxxxxx>: > On Fri, 20 Aug 2010 10:27:53 -0400 (EDT), Alan Stern wrote: >> On Thu, 19 Aug 2010, Dennis Nezic wrote: >> >> > Gah. You're right! The drive works fine (at usb2 speeds / ehci) on >> > my other linux laptop (the one that had MSWindows previously)!? >> > >> > So it works with: >> > 00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW >> > (ICH6 Family) USB2 EHCI Controller (rev 04) >> > >> > But not with: >> > 00:13.2 USB Controller: ATI Technologies Inc IXP SB400 >> > USB2 Host Controller >> > >> > Why? :S >> >> How would I know? I already told you my best guess: The hardware is >> slightly miscalibrated, and as a result that particular controller >> doesn't work well with that particular device. While it might be >> caused by a hardware bug in the controller, it's hard to know what >> that bug is or how to work around it. >> >> Do other high-speed devices work okay with the SB400 controller? > > Yes, i've used a bunch of usb2 devices before without any problems. > > Any suggestions on how to go about debugging this? Some kind of > usb-wire sniffer? Maybe the controller does not pass usb certification. If you do want to know the reason, you can test the eye diagram of the usb host controller. -- Lei Ming -- 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
