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From: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
To: "Zachary Amsden" <zach@vmware.com>
Cc: "Andi Kleen" <ak@muc.de>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Andrew Morton" <akpm@osdl.org>,
	"Rusty Russell" <rusty@rustcorp.com.au>,
	"Jeremy Fitzhardinge" <jeremy@goop.org>,
	"Chris Wright" <chrisw@sous-sol.org>
Subject: Re: [PATCH 9/11] Panic delay fix
Date: Wed, 7 Feb 2007 09:58:57 -0500	[thread overview]
Message-ID: <d120d5000702070658l1c018565n34a6d8814a20184d@mail.gmail.com> (raw)
In-Reply-To: <45C8FA2D.6010706@vmware.com>

On 2/6/07, Zachary Amsden <zach@vmware.com> wrote:
> Andi Kleen wrote:
> > On Mon, Feb 05, 2007 at 07:53:30PM -0800, Zachary Amsden wrote:
> >
> >> Failure to use real-time delay here causes the keyboard to become demonically
> >> possessed in the event of a kernel crash, with wildly blinking lights and
> >> unpredictable behavior.  This has resulted in several injuries.
> >>
> >
> > There must be a reason why it wasn't default before. Has this
> > reason changed?
> >
>
> This only matters under paravirt; non-paravirt kernels and kernels
> running on native hardware will always behave properly.
>
> But paravirtualized kernels with fake devices have no need to udelay to
> accommodate slow hardware - the hardware is just virtual.  The
> USE_REAL_TIME_DELAY define allows udelay to be specifically reverted
> back to being a real delay.  There are only a couple cases where it
> matters - one is booting APs on SMP systems (there is a real delay
> before they come up), and one is any hardware that drives world
> interacting devices - such as keyboard LEDs in a panic loop.
>

I am confused - does i8042 talk to a virtual or real hardware here? In
any case I think you need to fix kernel/panic.c to have proper
(m)delay, not mess with i8042.

-- 
Dmitry

  parent reply	other threads:[~2007-02-07 14:59 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-06  3:53 Zachary Amsden
2007-02-06 12:27 ` Andi Kleen
2007-02-06 21:59   ` Zachary Amsden
2007-02-07 12:35     ` Pavel Machek
2007-02-07 20:36       ` Rusty Russell
2007-02-07 22:23         ` Zachary Amsden
2007-02-08 14:43         ` Dmitry Torokhov
2007-02-08 21:26           ` Zachary Amsden
2007-02-08 21:37             ` Dmitry Torokhov
2007-02-14 12:26         ` Pavel Machek
2007-02-14 19:47           ` Zachary Amsden
2007-02-14 12:52         ` Alan
2007-02-14 20:04           ` Zachary Amsden
2007-02-14 21:34             ` Alan
2007-02-14 21:53               ` Zachary Amsden
2007-02-15  0:33                 ` Alan
2007-02-15 10:17             ` Pavel Machek
2007-02-15 23:42               ` Zachary Amsden
2007-02-15 23:49                 ` Pavel Machek
2007-02-15 23:50                 ` Jeremy Fitzhardinge
2007-02-16  3:22                 ` Rusty Russell
2007-02-07 14:58     ` Dmitry Torokhov [this message]
2007-02-07 22:31       ` Zachary Amsden
2007-02-08  8:24         ` Andi Kleen
2007-02-08  9:08           ` Zachary Amsden
2007-02-08 13:33             ` Andi Kleen
2007-02-08 14:41               ` Dmitry Torokhov
2007-02-14 12:49             ` Alan
2007-02-14 22:51 ` Rusty Russell
2007-02-15  0:28   ` Alan
2007-02-15 13:35   ` Dmitry Torokhov

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