On Tue, 27 Mar 2007, Casey Ballentine wrote: > On 3/27/07, Alan Stern <[EMAIL PROTECTED]> wrote: > > That doesn't mean it's working right. But you didn't collect a trace log > > so we can't see what actually happened. > > Sorry. See attached bus analyzer output when connected to a WinXP > machine. I didn't send the whole trace because it's pretty long and I > didn't want to risk this message getting bounced. Let me know if I > got the right information.
The interesting part is here. This is Windows apparently asking for the hub descriptor: > [232] 0:02.817.471.812 / SETUP > Duration = 2812 ns > Length = 3 bytes > > 0000: 2D 01 E8 > > > [233] 0:02.817.474.979 / DATA0 > Duration = 8145 ns > Length = 11 bytes > > 0000: C3 A0 06 00 00 00 00 47 > 0008: 00 E0 7C The wValue word (bytes 3 & 4) in that setup request is equal to 0x0000. However according to the USB spec, it must be equal to 0x2900. (The high-order byte is the descriptor type and 0x29 represents a hub descriptor.) Compare this to entry [225] in the Linux log. In other words, Windows has sent an invalid request and the device accepted it. If you look a little farther down at the start of the device's reply: > [237] 0:02.818.474.687 / DATA1 > Duration = 8166 ns > Length = 11 bytes > > 0000: 4B 09 29 03 0D 00 16 64 > 0008: 02 A0 6B you'll see that the descriptor type in the reply (byte 2) is indeed equal to 0x29. So the device did send a hub descriptor even though Windows had asked for an invalid descriptor. Perhaps that indicates where the bug is. The firmware is set up to accept an incorrect request, so maybe it can't handle correct requests. How ironic. > Apparently our hardware engineers don't trust the usbmon output. They > insisted, I acquiesced. Well, just tell them they should should trust it more than they should trust the firmware they are testing. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
