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

[Pavel Machek <pavel@suse.cz>]

Hi!

> > There was discussion about this issue several months ago (intel's ml), looks
> > people forgot to take action after the discussion. The spec owner said 64bit
> > vector is used in protected mode. That is if OS sets it, wakeup code is
> > called in protected mode by BIOS. So the 64-bit vector shouldn't be used.   
> 
> 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.

Hmm, nice.

64-bit waking is the one that is 'recommended' to use, right? Could we
get some strange machines (kohjisha?) to jump to the waking vector by
using 64-bit one?

Do windows use 32-bit or 64-bit vector?

> 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>

ACK.

> ---
>  drivers/acpi/hardware/hwsleep.c |   37 +++++++++++--------------------------
>  1 file changed, 11 insertions(+), 26 deletions(-)
> 
> Index: linux-2.6/drivers/acpi/hardware/hwsleep.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/hardware/hwsleep.c
> +++ linux-2.6/drivers/acpi/hardware/hwsleep.c
> @@ -78,19 +78,17 @@ acpi_set_firmware_waking_vector(acpi_phy
>  		return_ACPI_STATUS(status);
>  	}
>  
> -	/* Set the 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.  Some systems (for example HP dv5-1004nr) are known
> +	 * to fail to resume if the 64-bit vector is used.
> +	 */
> +	if (facs->version >= 1)
> +		facs->xfirmware_waking_vector = 0;
>  
> -	if ((facs->length < 32) || (!(facs->xfirmware_waking_vector))) {
> -		/*
> -		 * ACPI 1.0 FACS or short table or optional X_ field is zero
> -		 */
> -		facs->firmware_waking_vector = (u32) physical_address;
> -	} else {
> -		/*
> -		 * ACPI 2.0 FACS with valid X_ field
> -		 */
> -		facs->xfirmware_waking_vector = physical_address;
> -	}
> +	facs->firmware_waking_vector = (u32)physical_address;
>  
>  	return_ACPI_STATUS(AE_OK);
>  }
> @@ -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);
>  }


-- 
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