linux-kernel - Re: [PATCH] x86 reboot: Remove inb

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Date:	Sat, 19 Jan 2008 09:00:40 -0800
From:	"Ray Lee" <ray-lk@...rabbit.org>
To:	"Alan Cox" <alan@...rguk.ukuu.org.uk>
Cc:	mingo@...hat.com, akpm@...l.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86 reboot: Remove inb_p usage

On Jan 19, 2008 7:44 AM, Alan Cox <alan@...rguk.ukuu.org.uk> wrote:
> We are driving a motherboard port so use a 2uS explicit delay at this
> point.
>
> Signed-off-by: Alan Cox <alan@...hat.com>
>
> diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.24-rc8-mm1/arch/x86/kernel/reboot.c linux-2.6.24-rc8-mm1/arch/x86/kernel/reboot.c
> --- linux.vanilla-2.6.24-rc8-mm1/arch/x86/kernel/reboot.c       2008-01-19 14:47:55.000000000 +0000
> +++ linux-2.6.24-rc8-mm1/arch/x86/kernel/reboot.c       2008-01-19 14:53:58.000000000 +0000
> @@ -319,9 +319,11 @@
>  {
>         int i;
>
> -       for (i = 0; i < 0x10000; i++)
> -               if ((inb_p(0x64) & 0x02) == 0)
> +       for (i = 0; i < 0x10000; i++) {
> +               if ((inb(0x64) & 0x02) == 0)
>                         break;
> +               udelay(2);
> +       }
>  }
>
>  void machine_emergency_restart(void)

Stupid question from the peanut gallery: If you're going to go through
all this, maybe it would be better to define an inline
isa_bus_delay(void) { udelay(2); } and use that instead? I can only
imagine some poor sod coming along later and wondering why there's a
udelay(2) there. OTOH, there is an inb right above it, so <shrug>.
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