acpi_vbios_reset hangs while vbetool works (Was: sporadic failure to wakeup from S3)

[David Brownlee <abs%netbsd.org@localhost>]

2011/9/5 Marko Schütz Schmuck <MarkoSchuetz%web.de@localhost>:
> At Mon, 05 Sep 2011 15:14:02 -0400,
> Marko Schütz Schmuck wrote:
>>
>> At Mon, 05 Sep 2011 15:06:26 -0400,
>> Marko Schtz Schmuck wrote:
>> >
>> > Recently, I am experiencing sporadic failure to wake from ACPI Sleep
>> > state S3.
>
> now using machdep.acpi_vbios_reset=0 together with appropriate vbetool
> invocations in /etc/powerd/scripts/sleep_button and I haven't had the
> failure to wake since, but it's only been a short time...
>
> When using 5.0.2 I never had to set machdep.acpi_vbios_reset=0 nor did
> I have to use vbetool.

Does anyone know if acpi_vbios_reset is doing anything intrinsically
different to vbetool reset, or possibly is it just doing it at a
different point in the resume?