Re: [PATCH] ACPI suspend: Always use the 32-bit waking vector

Rafael J. Wysocki
2008-09-17T05:41:33Z

On Monday, 15 of September 2008, Pavel Machek wrote:
> Hi!
>
> > Well, I read this part of the spec (2.0c, 3.0b) more carefully and it matches
> > what you're saying. Moreover, my understanding of it is that we should
> > actually _clear_ the 64-bit vector on systems that support it, because
> > otherwise the BIOS is supposed to use it and call the wake-up code in protected
> > mode.
> >
> > The appended patch is based on this observation.
> >
> > Thanks,
> > Rafael
> >
> > ---
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> >
> > ACPI suspend: Always use the 32-bit waking vector
> >
> > According to the ACPI specification 2.0c and later, the 64-bit waking vector
> > should be cleared and the 32-bit waking vector should be used, unless we want
> > the wake-up code to be called by the BIOS in Protected Mode. Moreover, some
> > systems (for example HP dv5-1004nr) are known to fail to resume if the 64-bit
> > waking vector is used. Therefore, modify the code to clear the 64-bit waking
> > vector, for FACS version 1 or greater, and set the 32-bit one before suspend.
> >
> > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > ---
> > drivers/acpi/hardware/hwsleep.c | 37 +++++++++++--------------------------
> > 1 file changed, 11 insertions(+), 26 deletions(-)
> >
> > @@ -134,20 +132,7 @@ acpi_get_firmware_waking_vector(acpi_phy
> > }
> >
> > /* Get the vector */
> > -
> > - if ((facs->length < 32) || (!(facs->xfirmware_waking_vector))) {
> > - /*
> > - * ACPI 1.0 FACS or short table or optional X_ field is zero
> > - */
> > - *physical_address =
> > - (acpi_physical_address) facs->firmware_waking_vector;
> > - } else {
> > - /*
> > - * ACPI 2.0 FACS with valid X_ field
> > - */
> > - *physical_address =
> > - (acpi_physical_address) facs->xfirmware_waking_vector;
> > - }
> > + *physical_address = (acpi_physical_address)facs->firmware_waking_vector;
> >
> > return_ACPI_STATUS(AE_OK);
> > }
>
> Actually, I guess we should kill acpi_get_firmware_waking_vector: It
> is completely useless, and it is indeed never used in whole Linux...

Well, it's under '#ifdef 0' anyway, but I wanted it to be consistent with the
code we actually use. :-)

Thanks,
Rafael