Re: ACPI S3 resume only reboots

[Alberto Piai <albeclemit-whZMOeQn8C0@public.gmane.org>]

On Thu, 14 Oct 2004 10:29:28 +0200
Alberto Piai <albeclemit-whZMOeQn8C0@public.gmane.org> wrote:

> On Wed, 13 Oct 2004 06:39:26 -0700
> "Pallipadi, Venkatesh" <venkatesh.pallipadi-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> wrote:
> 
> > >> I suspected 'pushl $0' cause reboot a little. I can't find 
> > >any fault in
> > >> the line. Is it the precise line to cause reboot?
> > >
> > >Yes, i tryed placing an infinite loop immediately before and 
> > >after that line, and that line causes reboot.
> > >
> > 
> > From the comment in those lines, push and pop are not required for all
> > platforms. Can you just comment out that push and pop and see how far
> > you can go.

I know it's not the most the effective way to proceed, but at least i tryed ;)
I've been moving around the pushl $0 (that causes reboot) to check if the code was still executing. That's what i found.

Code from arch/i386/kernel/acpi/wakeup.S:
[...]
	mov	$(wakeup_stack - wakeup_code), %sp		# Private stack is needed for ASUS board
	movw	$0x0e00 + 'S', %fs:(0x12)

	#pushl	$0	###THIS LINE CAUSES REBOOT!		# Kill any dangerous flags
	#popfl

	movl	real_magic - wakeup_code, %eax
	cmpl	$0x12345678, %eax
	jne	bogus_real_magic

	testl	$1, video_flags - wakeup_code
		### If I put pushl $0 here, it causes reboot. code is still alive.
 	jz	1f
		## pushl $0 here doesn't make reboot (hang on wakeup)
	
	lcall   $0xc000,$3
	
	movw	%cs, %ax
	movw	%ax, %ds					# Bios might have played with that
	movw	%ax, %ss
[...]

What happens with that jz 1f? is it supposed to enter the jmp?

Thanks,
Alberto


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