Re: [PATCH] x86: usb debug port early console

From: Andrew Morton
Date: Wed Jul 23 2008 - 16:13:38 EST


On Wed, 23 Jul 2008 12:52:20 -0700
Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:

>
>
> based on work from Eric, and add some timeout so don't dead loop when debug device
> is not installed
>
>
> ...
>
> +static void dbgp_mdelay(int ms)
> +{
> + int i;
> + while (ms--) {
> + for (i = 0; i < 1000; i++)
> + outb(0x1, 0x80);
> + }
> +}

hm. port 80 has a guaranteed one microsecond? Why not
udelay()/mdelay()/etc?

> +static void dbgp_breath(void)
> +{
> + /* Sleep to give the debug port a chance to breathe */
> +}

I expect the compiler will optimise away any calls to this.

>
> ...
>
> --- linux-2.6.orig/arch/x86/kernel/head64.c
> +++ linux-2.6/arch/x86/kernel/head64.c
> @@ -72,6 +72,8 @@ static void __init copy_bootdata(char *r
> }
> }
>
> +extern void __init enable_debug_console(char *buf);

Please always pass all patches through scripts/checkpatch.pl.

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