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From: antirez <antirez@invece.org>
To: "Dunlap, Randy" <randy.dunlap@intel.com>
Cc: "'antirez@invece.org'" <antirez@invece.org>,
	Greg KH <greg@wirex.com>, Heitzso <xxh1@cdc.gov>,
	"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
	"'Johannes Erdfelt'" <johannes@erdfelt.com>
Subject: Re: USB broken in 2.4.0
Date: Sat, 6 Jan 2001 04:50:50 +0100	[thread overview]
Message-ID: <20010106045050.C1748@prosa.it> (raw)
In-Reply-To: <D5E932F578EBD111AC3F00A0C96B1E6F07DBDEBE@orsmsx31.jf.intel.com>
In-Reply-To: <D5E932F578EBD111AC3F00A0C96B1E6F07DBDEBE@orsmsx31.jf.intel.com>; from randy.dunlap@intel.com on Fri, Jan 05, 2001 at 04:48:00PM -0800

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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  reply	other threads:[~2001-01-06  1:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-01-06  0:48 USB broken in 2.4.0 Dunlap, Randy
2001-01-06  3:50 ` antirez [this message]
2001-01-06  1:53   ` Johannes Erdfelt
  -- strict thread matches above, loose matches on Subject: below --
2001-01-08 15:38 Heitzso
2001-01-08 17:54 ` antirez
2001-01-05 17:38 Heitzso
2001-01-05 18:00 ` Greg KH
2001-01-05 23:04   ` antirez
2001-01-06  2:39     ` antirez
2001-01-06  3:40       ` antirez

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