linux-kernel - Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

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Message-ID: <4765D43E.1010800@gmail.com>
Date:	Mon, 17 Dec 2007 02:43:26 +0100
From:	Rene Herman <rene.herman@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	"H. Peter Anvin" <hpa@...or.com>, Paul Rolland <rol@...917.net>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Pavel Machek <pavel@....cz>, "David P. Reed" <dpreed@...d.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	rol@...be.net
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

On 16-12-07 16:22, Ingo Molnar wrote:

> looks good to me. Could you please also provide three more controls that 
> i suggested earlier:
> 
>  - a boot option enabling/disabling the udelay based code
>  - a .config method of enabling/disabling the udelay based code
>  - a sysctl to toggle it
> 
> if we want to clean this all up we'll need as many controls as possible.

This version does the boot and the .config option but not the sysctl. It 
makes for clumsy code and I don't believe it provides for much added value 
as soon as you have the boot option. I am moreover not completely confident 
about things such as paravirt liking the possibility of the native_io_delay 
being changed out from under them at unpredictable times.

So how is this? Also fixes a few problems with the previous version.

  Documentation/kernel-parameters.txt |    8 ++
  arch/x86/Kconfig.debug              |    9 +++
  arch/x86/boot/compressed/misc_32.c  |    8 +-
  arch/x86/boot/compressed/misc_64.c  |    8 +-
  arch/x86/kernel/Makefile_32         |    2
  arch/x86/kernel/Makefile_64         |    2
  arch/x86/kernel/io_delay.c          |  103 
++++++++++++++++++++++++++++++++++++
  arch/x86/kernel/setup_32.c          |    2
  arch/x86/kernel/setup_64.c          |    2
  include/asm-x86/io_32.h             |    6 --
  include/asm-x86/io_64.h             |   27 +++++----
  11 files changed, 152 insertions(+), 25 deletions(-)

Rene.

View attachment "dmi-io_delay2.diff" of type "text/plain" (12738 bytes)