Re: USB broken in 2.4.0

antirez (antirez@invece.org)
Sat, 6 Jan 2001 04:50:50 +0100

On Fri, Jan 05, 2001 at 04:48:00PM -0800, Dunlap, Randy wrote:
> This rings a small bell with me.
> There was a change by Dan Streetman IIRC to limit
> usbdevfs bulk transfers to PAGE_SIZE (4 KB for x86,
> or 0x1000). Anything larger than that returns
> an error (-EINVAL).

Yes, devio.c, proc_bulk():

if (len1 > PAGE_SIZE)
return -EINVAL;

Actually it is the max transfer size I can reach.
I guess that to limit the page size can be an impementation
advantage but it may slow-down a bit some userspace driver.
I feel that even if the linux way is to implement the USB
drivers in kernel space a full-featured USB user space access
should be allowed.

antirez
(please cc me)

-- 
Salvatore Sanfilippo              |                      <antirez@invece.org>
http://www.kyuzz.org/antirez      |      PGP: finger antirez@tella.alicom.com
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