On Mon, 21 Jun 2004, Zan Lynx wrote: > I have attached copies of /proc/driver/uhci/0000:00:13.1 > > I can't tell you about the interrupts because other devices on IRQ 11 > are also interrupting. There isn't much I can do about the SCSI > controller. I need that. :-) > > If you think it's important, I could try moving the SCSI controller > around to see if I can get a different IRQ.
It might be important. The "before" and "after" copies were uninteresting; they looked totally normal. But the "during" copy was different. It showed that the USB controller had finished receiving a data transfer from the mouse, but it apparently had not issued an interrupt request (because the transfer structures had not been removed from the active-lists) and it was not trying to issue one. Another difference was that the "during" copy showed the transfer had the SPD (Short Packet Detect) flag set. In principle that should not have caused this sort of problem. In fact, the UHCI specification says that when SPD is set and a short packet occurs (this was a short packet; the request was for 8 bytes and the mouse only sent 6) then an interrupt request is issued and the queue header is not updated. But it was updated, and an interrupt wasn't requested. The most likely possibility is that your controller didn't issue an interrupt request when it was supposed to. In other words, a hardware failure. That's my best guess for now. It doesn't explain why things appear to work okay under 2.6.5, though, or why SPD was set. It's possible the two things are related; one of the things that changed between 2.6.5 and 2.6.7 was the handling of the SPD flag. The best way to confirm that the hardware is at fault is to try running the same software on another computer with the same type of USB controller. Maybe you can figure out some way to do that. It also would be nice to know why SPD was set. That's controlled entirely by software. In this case, the mouse driver or HID driver would have had to ask for that flag. I don't know any reason why they would, however, nor do I see any place in the code where they do. Alan Stern ------------------------------------------------------- This SF.Net email sponsored by Black Hat Briefings & Training. Attend Black Hat Briefings & Training, Las Vegas July 24-29 - digital self defense, top technical experts, no vendor pitches, unmatched networking opportunities. Visit www.blackhat.com _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
