usb-uhci works differently, so I don't think it could happen the same way. As for interrupts being disabled, that's a good question. I think there are some tools to measure that somewhere.
IIRC two sources that are significant are IDE and APM. JE On Mon, Mar 10, 2003, Brian Williams <[EMAIL PROTECTED]> wrote: > Could this happen with the usb-uhci code as well? I didn't see a > similar completion list. > > Is there a good way to track down how long and where interrupts are > being disabled? > > Thanks. > > --Brian > > -----Original Message----- > From: Johannes Erdfelt [mailto:[EMAIL PROTECTED] > Sent: Sunday, March 09, 2003 10:32 AM > To: Jouni Ryno > Cc: [EMAIL PROTECTED] > Subject: Re: [linux-usb-devel] Continuous iso transfer completes out of > order ? (2.4.20) > > On Sun, Mar 09, 2003, Jouni Ryno <[EMAIL PROTECTED]> wrote: > > I'm developing driver for EZUSB-based system. When I use continuous > > iso-transfer (several urbs connected in the ring), every 986 > (sometimes > > +-3) I get 1 or more urbs, which complete in reverse order. > > > > For example, start_frames in completion routine show up like > > 20, 21, 23, 22, 24. The next error would be like 6, 7, 9, 8, 10 ... > > Sometimes even 0, 1, 6, 5, 4, 3, 2, 7, 8 ... > > > > No missing data, just reverse order. > > > > This is with 2.4.20, UHCI (uhci.o) in Dell Inspiron. > > > > Is this a known phenomena, my misunderstanding of something or a bug > ... > > Well, it's probably it just an artifact from this code: > > list_add(&urbp->complete_list, &uhci->complete_list); > > If we complete multiple URBs during one frame, the completion handlers > will be called in reverse order. This may not be what is expected. If > you can, try changing that to list_add_tail and see if it works like you > expect. > > However, I'm more worried that this is even happening in the first > place. Why would we have more than 1 (5 in one example!) complete in one > frame. Sounds like something is turning off interrupts for a LONG time. > > Do you have APM turned on by chance? The frequency it happens is very > suspicious (a hair less than every second) > > > By the way, is there a thumb rule, of how many urbs one should have in > a > > ring ? > > Atleast 3. It all depends on your latency and reliability requirements. > > JE > > > > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf > _______________________________________________ > [EMAIL PROTECTED] > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
