Subject: Re: usb control endpoint exclusive access
To: Lennart Augustsson <email@example.com>
From: Quentin Garnier <firstname.lastname@example.org>
Date: 05/17/2005 08:33:31
Content-Type: text/plain; charset=us-ascii
On Tue, May 17, 2005 at 08:14:42AM +0200, Lennart Augustsson wrote:
> Berndt Josef Wulf wrote:
> >3) No support to open devices for read and write access by separate=20
> Now this one is tricky. Linux has a different semantics for close() in
> the kernel than NetBSD. Linux calls the device open() every time the
> device is opened and close() every time the device is closed.
> NetBSD calls open() on every open, but close() only on the last close.
> The NetBSD behaviour makes it very difficult to have separate read&write
> processes. :(
It is rather easy to do clonable devices on NetBSD, now. See, e.g.,
tap(4) (in src/sys/net/if_tap.c) which actually shows both access
Quentin Garnier - email@example.com - cube@NetBSD.org
"When I find the controls, I'll go where I like, I'll know where I want
to be, but maybe for now I'll stay right here on a silent sea."
KT Tunstall, Silent Sea, Eye to the Telescope, 2004.
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