Hi,

I just started developing a driver for the USB 2.0 data acquisition
board I just built.  I based the driver design on usb-skeleton.c file.
Everything is working fine so far, but I am having a throughput problem.


I am currently testing the device plugged into a USB 1 controller.

When I do several back to usb_bulk_msg calls (64 byte writes),  I notice
each one takes about 1 ms to complete.  I decided to probe the usb trace
on the hardware.  I noticed that even when the device and driver are
idle, I see packets being transmitted every 1ms.  I am showing my
ignorance here, but what are these?  Second thing I notice is that when
I run these back to back bulk transfers, I don't see a burst off them on
the O-scope.  Each bulk transfer come at the same place following the
"unknown" packets.  

This is what is slowing my bulk transfers down.  How do a make my
transfers use all available bandwidth and not just this one slot every 1
ms?  Do I have to use a bunch of linked urbs?

Thanks,

Torry Akins
Remote Sensing Lab
University of Kansas



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