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SubjectRe: beeping patch for debugging acpi sleep
On Sat, 9 Jun 2007 15:08:17 +0200
Pavel Machek <pavel@ucw.cz> wrote:

>
> Starting beeper as soon as ACPI sleep returns is very useful in
> debugging "apparently dead" machines. If it beeps at all, it makes
> sense to start playing with CMOS tracer.
>
> Signed-off-by: Pavel Machek <pavel@suse.cz>
>
> diff --git a/arch/i386/kernel/acpi/wakeup.S b/arch/i386/kernel/acpi/wakeup.S
> index b781b38..cbf136e 100644
> --- a/arch/i386/kernel/acpi/wakeup.S
> +++ b/arch/i386/kernel/acpi/wakeup.S
> @@ -11,7 +11,22 @@ # Do we need to deal with A20? It is oka
> #
> # If physical address of wakeup_code is 0x12345, BIOS should call us with
> # cs = 0x1234, eip = 0x05
> -#
> +#
> +
> +#define BEEP \
> + inb $97, %al; \
> + outb %al, $0x80; \
> + movb $3, %al; \
> + outb %al, $97; \
> + outb %al, $0x80; \
> + movb $-74, %al; \
> + outb %al, $67; \
> + outb %al, $0x80; \
> + movb $-119, %al; \
> + outb %al, $66; \
> + outb %al, $0x80; \
> + movb $15, %al; \
> + outb %al, $66;
>
> ALIGN
> .align 4096
> @@ -20,6 +35,9 @@ wakeup_code:
> wakeup_code_start = .
> .code16
>
> +# Uncomment this to make your computer start producing ugly noise as soon
> +# as BIOS returns to this real-mode entry point.
> +# BEEP
> movw $0xb800, %ax
> movw %ax,%fs
> movw $0x0e00 + 'L', %fs:(0x10)
>

How does the beep get turned off again?

Should the BEEP line be uncommented (in -mm at least)?

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