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. > ISTR this bug dating from back in the 2.4 days. Happens very > intermittently, > and never (any longer) to me ... after lots of driver fixes (little races) > in the 2.5.early days, I stopped being able to reproduce it. Yes, we first encountered it in 2.4 and upgraded our platform to 2.6 and ported the device driver in hopes it had been fixed. It seems to behave "better" in 2.4, in that it doesn't lock up the host controller driver, although the read completion handler never gets called so it's still messy on a device driver level. I'd hate to have to downgrade as a workaround. > 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. > ISTR trying the obvious "pretend INTR_SF happended" but seeing misbehavior > (likely > oopsing, but that was quite a few years ago by now), which is why the code > still > leaks that memory. > > 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. Mike ------------------------------------------------------------------------- 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
