From: Len Brown <len.brown@intel.com>
To: Juerg Billeter <juerg@paldo.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix reloading GDT on ACPI S3 wakeup
Date: 11 Apr 2005 13:17:16 -0400 [thread overview]
Message-ID: <1113239836.2418.38.camel@d845pe> (raw)
In-Reply-To: <1112976854.8880.15.camel@juerg-p4.bitron.ch>
I've applied Nickolai's patch -- thanks for the ping.
-Len
On Fri, 2005-04-08 at 12:14, Juerg Billeter wrote:
> Hi
>
> This patch - based on
> http://marc.theaimsgroup.com/?l=linux-kernel&m=110055503031009&w=2 -
> makes ACPI S3 wakeup work for me on a ThinkPad T40p laptop with a SMP
> kernel. Without it only UP kernels work. I've been using the patch for
> three months now without any issues.
>
> The ACPI resume code currently uses a real-mode 16-bit lgdt
> instruction
> to reload the GDT. This only restores the lower 24 bits of the GDT
> base
> address. In recent SMP kernels, the GDT seems to have moved out of
> the
> lower 16 megs, thereby causing the ACPI resume to fail -- an invalid
> GDT
> was being loaded.
>
> Regards,
>
> Juerg
>
> --
> Signed-off-by: Juerg Billeter <juerg@paldo.org>
>
> diff -uNr linux-2.6.10.orig/arch/i386/kernel/acpi/wakeup.S
> linux-2.6.10/arch/i386/kernel/acpi/wakeup.S
> --- linux-2.6.10.orig/arch/i386/kernel/acpi/wakeup.S 2004-12-24
> 22:34:26.000000000 +0100
> +++ linux-2.6.10/arch/i386/kernel/acpi/wakeup.S 2005-01-08
> 23:34:38.551471486 +0100
> @@ -74,8 +74,9 @@
> movw %ax,%fs
> movw $0x0e00 + 'i', %fs:(0x12)
>
> - # need a gdt
> - lgdt real_save_gdt - wakeup_code
> + # need a gdt -- use lgdtl to force 32-bit operands, in case
> + # the GDT is located past 16 megabytes
> + lgdtl real_save_gdt - wakeup_code
>
> movl real_save_cr0 - wakeup_code, %eax
> movl %eax, %cr0
>
>
>
>
prev parent reply other threads:[~2005-04-11 17:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-08 16:14 Juerg Billeter
2005-04-11 17:17 ` Len Brown [this message]
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