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

Pavel Machek
2008-09-17T07:28:19Z

On Wed 2008-09-17 07:46:42, Rafael J. Wysocki wrote:
> 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. :-)

Yes, removing dead code is separate battle, I see.
Pavel
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