From: David Brownell <david-b@pacbell.net>
To: linux-usb-devel@lists.sourceforge.net
Subject: Re: [linux-usb-devel] RE: [PATCH] Early USB handoff
Date: Thu, 2 Sep 2004 16:44:51 -0700
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Cc: "Aleksey Gorelov" <Aleksey_Gorelov@Phoenix.com>,
       "Alan Cox" <alan@lxorguk.ukuu.org.uk>,
       "Pete Zaitcev" <zaitcev@redhat.com>,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
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On Thursday 02 September 2004 1:26 pm, Aleksey Gorelov wrote:

>   While still in real mode, BIOS takes care of interrupts from 
> devices. But once OS takes control over and goes to protected 
> mode, there is no easy way for BIOS to detect that and disable HC.

I find myself a bit unsettled at the notion of not really being
able to blame this behavior on BIOS bugs.  What's the world
coming to any more?!


> So, one should either avoid 'sharing' it with other devices (at
> IRQ routing stage), or reprogram HC in native OS mode first (at 
> least disable interrupts).

That sounds like it could explain lots of the init/irq problems we've
had on various systems.  Makes me a lot more interested in seeing
this fix go in ... :)

For backwards compatibility, the early reset should not be the
default.  There aren't many systems where it's a problem.

- Dave
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