[Qemu-devel] ACPI 5.1: 7.3.2 System \_Sx states

[Qemu-devel] ACPI 5.1: 7.3.2 System \_Sx states

[Michael S. Tsirkin]

Hello!
I have noticed the following inconsistency in ACPI spec 5.1.
7.3.2 System \_Sx states

States:

Return Value:
A Package containing an Integer containing register values for sleeping

It goes on to specify Table 7-221 System State Package
which describes a byte array in terms of byte length/byte offsets.

In practice, I see that implementations define \_Sx
as a package containing 4 integers.

Here's an example package generated by IASL:

      52:          Name(_S4, Package(0x04) {
      53:              0x2,
      54:              0x2,
      55:              Zero,
      56:              Zero
      57:          })

00000091:  08 5F 53 34 5F .........    "._S4_"
00000096:  12 08 04 0A 02 0A 02 00     "........"
0000009E:  00 .....................    "."

In other words, there are 4 integer values, and these are
not at offsets specified by the spec.

Suggested corrected wording:

Return Value:
A Package containing a list of 4 Integers containing register values for sleeping

and update Table 7-221 System State Package

as follows:


Type		Description

Integer 	Value for PM1a_CNT.SLP_TYP register to enter this system state. On
		HW-reduced
		platforms, this is the HW-reduced Sleep Type value for
		SLEEP_CONTROL_REG.SLP_TYP.

Integer		Value for PM1b_CNT.SLP_TYP register to enter this system
		state. To enter any
		given state, OSPM must write the PM1a_CNT.SLP_TYP register before the
		PM1b_CNT.SLP_TYP register. On HW-reduced platforms, this value is
		ignored.

Integer		Reserved. This value is ignored by the OSPM.
Integer		Reserved. This value is ignored by the OSPM.

-- 
MST

Re: [Qemu-devel] ACPI 5.1: 7.3.2 System \_Sx states

[Doran, Mark]

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Thanks for the report.  You might want to bring this to the attention of
Dean Nelson and/or Al Stone -- as regular attendees of the ACPI Work Group
they can file an ECR or show you how to do that if that's appropriate.

--
Cheers,
 
Mark.
 

> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Sunday, March 8, 2015 4:42 AM
> To: Doran, Mark
> Cc: dong.wei@hp.com; qemu-devel@nongnu.org
> Subject: ACPI 5.1: 7.3.2 System \_Sx states
> 
> Hello!
> I have noticed the following inconsistency in ACPI spec 5.1.
> 7.3.2 System \_Sx states
> 
> States:
> 
> Return Value:
> A Package containing an Integer containing register values for sleeping
> 
> It goes on to specify Table 7-221 System State Package which describes a
> byte array in terms of byte length/byte offsets.
> 
> In practice, I see that implementations define \_Sx as a package
> containing 4 integers.
> 
> Here's an example package generated by IASL:
> 
>       52:          Name(_S4, Package(0x04) {
>       53:              0x2,
>       54:              0x2,
>       55:              Zero,
>       56:              Zero
>       57:          })
> 
> 00000091:  08 5F 53 34 5F .........    "._S4_"
> 00000096:  12 08 04 0A 02 0A 02 00     "........"
> 0000009E:  00 .....................    "."
> 
> In other words, there are 4 integer values, and these are not at offsets
> specified by the spec.
> 
> Suggested corrected wording:
> 
> Return Value:
> A Package containing a list of 4 Integers containing register values for
> sleeping
> 
> and update Table 7-221 System State Package
> 
> as follows:
> 
> 
> Type		Description
> 
> Integer 	Value for PM1a_CNT.SLP_TYP register to enter this system
> state. On
> 		HW-reduced
> 		platforms, this is the HW-reduced Sleep Type value for
> 		SLEEP_CONTROL_REG.SLP_TYP.
> 
> Integer		Value for PM1b_CNT.SLP_TYP register to enter this
system
> 		state. To enter any
> 		given state, OSPM must write the PM1a_CNT.SLP_TYP register
> before the
> 		PM1b_CNT.SLP_TYP register. On HW-reduced platforms, this
value
> is
> 		ignored.
> 
> Integer		Reserved. This value is ignored by the OSPM.
> Integer		Reserved. This value is ignored by the OSPM.
> 
> --
> MST

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