admin-guide/acpi/ssdt-overlays.rst

1 .. SPDX-License-Identifier: GPL-2.0
7 In order to support ACPI open-ended hardware configurations (e.g. development
19 user defined SSDT tables that contain the board specific information.
60     ASL Optimizing Compiler version 20140214-64 [Mar 29 2014]
61     Copyright (c) 2000 - 2014 Intel Corporation
63     ASL Input:     minnomax.asl - 30 lines, 614 bytes, 7 keywords
64     AML Output:    minnowmax.aml - 165 bytes, 6 named objects, 1 executable opcodes
74 This option allows loading of user defined SSDTs from initrd and it is useful
91     mkdir -p kernel/firmware/acpi
96     find kernel | cpio -H newc --create > /boot/instrumented_initrd
103 allows a persistent, OS independent way of storing the user defined SSDTs. There
104 is also work underway to implement EFI support for loading user defined SSDTs
120 "Name-GUID" and that the first 4 bytes in the file (little-endian format)
128     #!/bin/sh -e
130     while ! [ -z "$1" ]; do
132             "-f") filename="$2"; shift;;
133             "-g") guid="$2"; shift;;
141             echo "Syntax: ${0##*/} -f filename [ -g guid ] name"
145     [ -n "$name" -a -f "$filename" ] || usage
149     [ -d "$EFIVARFS" ] || exit 2
151     if stat -tf $EFIVARFS | grep -q -v de5e81e4; then
152             mount -t efivarfs none $EFIVARFS
156     [ -n "$guid" ] || guid=$(find "$EFIVARFS" -name "$name-*" | head -n1 | cut -f2- -d-)
159     [ -n "$guid" ] || guid="$(cat /proc/sys/kernel/random/uuid)"
163     /bin/echo -ne "\007\000\000\000" | cat - $filename > $tmp
164     dd if=$tmp of="$EFIVARFS/$name-$guid" bs=$(stat -c %s $tmp)
170 This option allows loading of user defined SSDTs from userspace via the configfs