From: Duncan Sands <duncan.sands@math.u-psud.fr>
To: Pete Zaitcev <zaitcev@redhat.com>
Subject: Re: MAX_USBFS_BUFFER_SIZE
Date: Fri, 3 Mar 2006 09:12:11 +0100
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> Have you ever considered how many TDs have to be allocated to transfer
> a data buffer this big? No, seriously. If your application cannot deliver
> the tranfer speeds with 16KB URBs, we ought to consider if the combination
> of our USB stack, usbfs, libusb and the application ought to get serious
> performance enhancing surgery. The problem is obviously in the software
> overhead.

If you queue a large number of 16KB urbs, rather than one jumbo urb,
does that make any difference to the number of TDs allocated?  I thought
TDs were allocated for all queued urbs at the moment they are queued...

Ciao,

Duncan.
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