On Fri, 15 Apr 2005, Konstantin Kletschke wrote:
> 1.) In 10% of all plug events of the WLAN stick the usb core tells > "Device Descriptor Read Error" with both of the ohci emulation framework > and with the isp116x-hcd driver. Is it save to blame the WLAN stick > itself to be being buggy? In all cases powercycling or replug yields in > perfect USB device enumeration. More info would be needed to pinpoint the culprit. Does this happen with other USB host controllers (no idea, whether you need to install linux-wlan-ng driver on test boxen or not)? In any case, you can recompile the driver with DEBUG, PTD_TRACE, and URB_TRACE enabled and post logs for a successful and a failing enumeration to compare. > 2.) I wan't to measure the performance of the USB bus and I wonder how > to do this best. Is it safe to use an usb-2.0 storage device for that? > What data rates do you gain with your hardware? It must not be exact or > something, I only wan't to be sure to use the hardware at 90% and > exclude systematical errors or something. Leaving aside what may be "the best" way to measure the USB performance, I did it with usb-2.0 memory stick, which was the only device attached at the measurement time. With this controller, it's in full speed mode, of course. Mounting a stick that contained a 16 MB file and issuing: time if=a_16MB_file_on_stick of=/dev/null bs=16k yielded here 717 kiB/s. By the way, for the current driver version the maximum possible transfer rate when performing bulk-only transfers to/from a single device is 812.5 kiB/s. Olav ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
