Subject: Re: usb control endpoint exclusive access
To: None <>
From: Lennart Augustsson <>
List: tech-kern
Date: 05/17/2005 08:14:42
Berndt Josef Wulf wrote:
> Current issues that I'm facing are 
> 1) Data bandwidth of USB2.0 interface not up-to-spec on the ugen device

This will require some work.  And the only reasonable way to do
the work is to have access to a device so you can test it.
I don't have one.  But maybe I should get one. :)

> 2) Lack of support for multiple access to USB control endpoint

Just commit your patch to fix this one.  I see no problem with that.

> 3) No support to open devices for read and write access by separate processes

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. :(

	-- Lennart