Date: Fri, 28 Jan 2011 09:48:27 +0100 From: Hans Petter Selasky <hselasky@c2i.net> To: "Daniel O'Connor" <doconnor@gsoft.com.au> Cc: freebsd-usb@freebsd.org Subject: Re: libusb performance on 8.1 Message-ID: <201101280948.27511.hselasky@c2i.net> In-Reply-To: <2E5206C4-9327-4270-8948-FD44C62C645D@gsoft.com.au> References: <9CF6C32F-E230-446B-94FC-C57F0F02B0E4@gsoft.com.au> <201101280858.05077.hselasky@c2i.net> <2E5206C4-9327-4270-8948-FD44C62C645D@gsoft.com.au>
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On Friday 28 January 2011 09:42:57 Daniel O'Connor wrote: > On 28/01/2011, at 18:28, Hans Petter Selasky wrote: > > For this kind of applications ISOCHRONOUS transfers should be used. Then > > you can have a double buffer guard in the range 1-56ms, regardless of > > the buffer size the hardware uses. > > Hmm, OK, I will have a look at changing it, although it is a bit of a pain > because you can't stall an ISO EP and I'm using stall to indicate an > error. Hi, There are some hard limits in the libusb source code. Just search for 16K in decimal. In the kernel the limit is bigger and I guess you don't need to change anything there. > Is it possible to change the amount that is buffered? This is a specialised > application so a custom kernel is no problem. Even a hint in the right > direction would be greatly appreciated :) > > > You could also try an XHCI controller, because the BULK buffering is done > > differently there. > > OK thanks, I'll try that too. --HPS
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