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Date:      Tue, 3 Mar 2009 15:16:02 +0100
From:      Hans Petter Selasky <hselasky@c2i.net>
To:        Artyom Mirgorodsky <man@email.com.ua>
Cc:        freebsd-usb@freebsd.org
Subject:   Re: Low perfomance when read from usb flash drive
Message-ID:  <200903031516.02744.hselasky@c2i.net>
In-Reply-To: <200903031130.35613.man@email.com.ua>
References:  <200903010045.44904.man@email.com.ua> <200903030850.01866.hselasky@c2i.net> <200903031130.35613.man@email.com.ua>

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On Tuesday 03 March 2009, Artyom Mirgorodsky wrote:
> >I know that certain AMD USB controllers perform less with the new USB
> > stack, but I've not been able to track down the issue.
>
> Yes, I have AMD platform (motherboard ASUS A8N-VM-CSM)
>
> >Can you try another PC having another CPU brand?
>
> Yes, I have already posted the result - 22 Mb/sec, much better than on my
> computer.
>
> >There might be some minor things that needs tuning like the NAK retry
> > counter. I suspect you have run into a timing issue with the hardware.
>
> Can I do anything to solve this problem or at least help you to track it
> down?

Edit: src/sys/dev/usb/controller/ehci.c

        if (usb2_get_speed(xfer->xroot->udev) == USB_SPEED_HIGH) {
                qh_endp |= (EHCI_QH_SET_EPS(EHCI_QH_SPEED_HIGH) |
                    EHCI_QH_DTC);
                if (methods != &ehci_device_intr_methods)
                        qh_endp |= EHCI_QH_SET_NRL(8);
        } else {

And tune to NRL value to 15. Recompile kernel and modules.

--HPS



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