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
