Re: OHCI hangs after failing to free resources
David Brownell <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Saturday 28 April 2007, Alan Stern wrote: > On Fri, 27 Apr 2007, Mike Nuss wrote: > > > So for smaller values of HZ, it would retry for > > longer. Was this the intended behavior? > > You're right; for some reason I was thinking that the argument to > schedule_timeout_interruptible() was in milliseconds, not jiffies. > > I don't know the intended behavior because I didn't write the code. In > principle one would think that retrying for 10 ms or even less would be > sufficient, since the SOF interrupt is supposed to occur every > millisecond. I think the intended behavior was to delay long enough to let me notice and look at the device-under-test to see if it was still live, before doing anything funky on the host side. It wasn't initially as clear that the hardware was flaking out. > Certainly it's possible. I don't know what led to the creation of the > ZFMicro quirk either, but Dave does. The person who developed that workaround found that the controller wasn't restarting properly after unlinks without the delays. The OHCI spec doesn't expect them; only that implementation. Again, the "INTR_SF lossage" has been observed on non-ZFMICRO implemntations. Nothing especially "modern" though; it could be that older OHCI implementations were tuned to expect certain driver bugs (*cough*microsoft*cough*) that have since been fixed. - Dave ------------------------------------------------------------------------- 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/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel