On Thu, 3 Nov 2005, David Brownell wrote: > > When I do see syslog messages, they look like this: > > > > Nov 2 20:51:38 daydream kernel: usb 1-8: device descriptor read/64, error > > -71 > > Nov 2 20:51:38 daydream last message repeated 3 times > > Nov 2 20:51:39 daydream kernel: usb 1-8: device not accepting address 14, > > error -71 > > Nov 2 20:51:39 daydream kernel: usb 1-8: device not accepting address 15, > > error -71 > > This is early enumeration code. In fact, the read/64 stuff doesn't need > to be done; there's only one ep0 maxpacket size possible for high (or low) > speed devices. One person reported some success with a patch that bypasses > the "guess the ep0 maxpacket" dance except for full speed (which is the only > case where it's necessary) ... one theory is that since that dance forces > devices into certain fault modes, either (a) devices don't always handle > those fault modes correctly, or (b) Linux doesn't. So bypassing those > fault modes could make them both happier.
One way to test this theory is to use the undocumented "old_scheme_first=y" parameter for the usbcore module. Alan Stern ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
