--- Alan Stern <[EMAIL PROTECTED]> wrote: > On Tue, 21 Sep 2004, Manoj Bhatta wrote: > > > Sorry for late reply . let me remind you about my > > driver . This is USB 1.1 device with isoc endpoint > of > > 840 bytes. i am trying to read through isoc by > > submitting 5 frames per URB . each frame of 840 > bytes > > . i am submitting 56 URBs . Testing at 2.6.4 as > well > > as 2.6.8-1 kernel . > > > > i try to get urb->start_frame and > > usb_get_current_frame_number() values . > > > > i found like this (not all kernel messages only > the > > above) > > > > urb->start_frame = 211 > > usb_get_current_frame_number()= 960 > > But _when_ did you find this? After submitting the > URB or after the > completion handler was called?
I got the messages after usb_submit_urb() call . > > > So for each URB submit urb->start_frame increases > > 5(since i am using 5 frames per URB) , > > Exactly as it should. > > > but > > usb_get_current_frame_number() does not increase > > always 5 , fisrt time for some (for 45 URBs) it is > > same , after that it increases 5 in interval . > > But at one point it(usb_get_current_frame_number) > > increases to 10 . some unpredictable like > increases > > 50 frames . Why it increases unpredictably ? > > Without knowing when you are calling > get_current_frame_number it's hard to > comment on this. But remember that the frame number > goes up by 1 every > millisecond. So if you delay 5 milliseconds between > calls, you'll see the > number go up by 5. Similarly if you delay by 10 ms > or by 50. I am submitting 56 URBs each of 5 frames . one frame is of 840byte (1 ms) . > > > And sometimes kernel messges "usb bandwidth would > have > > FAILED" . > > Don't worry about that. It's just a warning, not an > error. (And the > warning is incorrect in your case.) > > > Is there any problem in bandwidth synchronization > > inbetween my device driver and UHCI driver? > > Since I don't know anything about your device > driver, you'll have to be > the person to answer that question. I dubgged bandwidth of UHCI when i am reading data from my device . my /proc/bus/usb/devices or usbview of UHCI Bandwidth tells 7392/900 (821 %) used and Total number of isochronous requests: 56 . > > Alan Stern > > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------------------------------- This SF.Net email is sponsored by: YOU BE THE JUDGE. Be one of 170 Project Admins to receive an Apple iPod Mini FREE for your judgement on who ports your project to Linux PPC the best. Sponsored by IBM. Deadline: Sept. 24. Go here: http://sf.net/ppc_contest.php _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
