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Date: Sun, 8 Mar 2015 12:42:29 +0100
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20150308114229.GA26769@redhat.com>
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Subject: [Qemu-devel] ACPI 5.1: 7.3.2 System \_Sx states
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To: mark.doran@intel.com
Cc: dong.wei@hp.com, qemu-devel@nongnu.org

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