On Fri, 27 Apr 2007, Mike Nuss wrote: > On Friday 27 April 2007, David Brownell wrote: > > On Friday 27 April 2007, Mike Nuss wrote: > > > Sometimes upon removing one of our devices (for which we have a > custom > > USB driver), OHCI fails > > > to free all the associated resources with the device. The problem is > > always associated > > > with the "IRQ INTR_SF lossage" message, which I assume is probably a > > hardware issue > > > > As far as I can tell, yes that's a hardware bug. Ramifications are > > unclear. > > > > On the other hand, the issue has been seen on more than one chipset, > so > > that > > may be overly simplistic. It's fortunately a rare error. > > > > In our environment I can reproduce it a couple of times a day by sending > a ton of data from our devices. A device will seem to stop sending data > (this is probably the start of the "bad condition" where INTR_SF never > happens), and if I then unplug the device, the bug shows up during the > cleanup.
"seem to" is probably right; I imagine the device is still working fine but the host controller is messed up. > > The expected interrupt never appears. INTR_SF is supposed to happen > every > > millisecond. > > Is it every millisecond regardless of bInterval? I'm still not entirely > clear on how the polling works. This has nothing to do with polling or bInterval. The host controller is supposed to generate an interrupt at the start of each frame (once per millisecond) provided the appropriate IRQ-enable flag is set. INTR_SF == INTeRrupt at Start of Frame. These are the interrupts which apparently don't occur -- although your debugging may uncover other problems. > > Someone who can reproduce this bug should try to fix it... > > > > - Dave > > Yes, please ;) I'd be happy to look at it myself, since I seem to be > alone in being able to reproduce it. But I'm obviously still pretty new > to the kernel USB stack. We'll be happy to help all we can. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
