Re: [patch] Fix GDT re-load on ACPI resume

From: David Weinehall
Date: Mon Nov 15 2004 - 18:07:15 EST

On Mon, Nov 15, 2004 at 03:35:14PM -0500, Nickolai Zeldovich wrote:
> 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 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.
> This simple patch adds the 0x66 prefix to lgdt, which forces it to load
> all 32 bits of the GDT base address, thereby removing any restrictions on
> where the GDT can be placed in memory. This makes ACPI resume work for me
> on a Thinkpad T40 laptop.

Sadly doesn't work for me. ACPI resume broke for me with
2.6.10-rc1-bk15 (possibly 14, but that one didn't compile), and this
patch does not fix it.

Regards: David Weinehall
/) David Weinehall <tao@xxxxxxxxxx> /) Northern lights wander (\
// Maintainer of the v2.0 kernel // Dance across the winter sky //
\) (/ Full colour fire (/
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