libusb performance on 8.1

[Hans Petter Selasky]

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