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? > 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 . 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. > 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. Alan Stern ------------------------------------------------------- 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
