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1 ACPI Debug Output
2
3
4The ACPI CA, the Linux ACPI core, and some ACPI drivers can generate debug
5output. This document describes how to use this facility.
6
7Compile-time configuration
8--------------------------
9
10ACPI debug output is globally enabled by CONFIG_ACPI_DEBUG. If this config
11option is turned off, the debug messages are not even built into the
12kernel.
13
14Boot- and run-time configuration
15--------------------------------
16
17When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages
18you're interested in. At boot-time, use the acpi.debug_layer and
19acpi.debug_level kernel command line options. After boot, you can use the
20debug_layer and debug_level files in /sys/module/acpi/parameters/ to control
21the debug messages.
22
23debug_layer (component)
24-----------------------
25
26The "debug_layer" is a mask that selects components of interest, e.g., a
27specific driver or part of the ACPI interpreter. To build the debug_layer
28bitmask, look for the "#define _COMPONENT" in an ACPI source file.
29
30You can set the debug_layer mask at boot-time using the acpi.debug_layer
31command line argument, and you can change it after boot by writing values
32to /sys/module/acpi/parameters/debug_layer.
33
34The possible components are defined in include/acpi/acoutput.h and
35include/acpi/acpi_drivers.h. Reading /sys/module/acpi/parameters/debug_layer
36shows the supported mask values, currently these:
37
38 ACPI_UTILITIES 0x00000001
39 ACPI_HARDWARE 0x00000002
40 ACPI_EVENTS 0x00000004
41 ACPI_TABLES 0x00000008
42 ACPI_NAMESPACE 0x00000010
43 ACPI_PARSER 0x00000020
44 ACPI_DISPATCHER 0x00000040
45 ACPI_EXECUTER 0x00000080
46 ACPI_RESOURCES 0x00000100
47 ACPI_CA_DEBUGGER 0x00000200
48 ACPI_OS_SERVICES 0x00000400
49 ACPI_CA_DISASSEMBLER 0x00000800
50 ACPI_COMPILER 0x00001000
51 ACPI_TOOLS 0x00002000
52 ACPI_BUS_COMPONENT 0x00010000
53 ACPI_AC_COMPONENT 0x00020000
54 ACPI_BATTERY_COMPONENT 0x00040000
55 ACPI_BUTTON_COMPONENT 0x00080000
56 ACPI_SBS_COMPONENT 0x00100000
57 ACPI_FAN_COMPONENT 0x00200000
58 ACPI_PCI_COMPONENT 0x00400000
59 ACPI_POWER_COMPONENT 0x00800000
60 ACPI_CONTAINER_COMPONENT 0x01000000
61 ACPI_SYSTEM_COMPONENT 0x02000000
62 ACPI_THERMAL_COMPONENT 0x04000000
63 ACPI_MEMORY_DEVICE_COMPONENT 0x08000000
64 ACPI_VIDEO_COMPONENT 0x10000000
65 ACPI_PROCESSOR_COMPONENT 0x20000000
66
67debug_level
68-----------
69
70The "debug_level" is a mask that selects different types of messages, e.g.,
71those related to initialization, method execution, informational messages, etc.
72To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT()
73statement.
74
75The ACPI interpreter uses several different levels, but the Linux
76ACPI core and ACPI drivers generally only use ACPI_LV_INFO.
77
78You can set the debug_level mask at boot-time using the acpi.debug_level
79command line argument, and you can change it after boot by writing values
80to /sys/module/acpi/parameters/debug_level.
81
82The possible levels are defined in include/acpi/acoutput.h. Reading
83/sys/module/acpi/parameters/debug_level shows the supported mask values,
84currently these:
85
86 ACPI_LV_INIT 0x00000001
87 ACPI_LV_DEBUG_OBJECT 0x00000002
88 ACPI_LV_INFO 0x00000004
89 ACPI_LV_INIT_NAMES 0x00000020
90 ACPI_LV_PARSE 0x00000040
91 ACPI_LV_LOAD 0x00000080
92 ACPI_LV_DISPATCH 0x00000100
93 ACPI_LV_EXEC 0x00000200
94 ACPI_LV_NAMES 0x00000400
95 ACPI_LV_OPREGION 0x00000800
96 ACPI_LV_BFIELD 0x00001000
97 ACPI_LV_TABLES 0x00002000
98 ACPI_LV_VALUES 0x00004000
99 ACPI_LV_OBJECTS 0x00008000
100 ACPI_LV_RESOURCES 0x00010000
101 ACPI_LV_USER_REQUESTS 0x00020000
102 ACPI_LV_PACKAGE 0x00040000
103 ACPI_LV_ALLOCATIONS 0x00100000
104 ACPI_LV_FUNCTIONS 0x00200000
105 ACPI_LV_OPTIMIZATIONS 0x00400000
106 ACPI_LV_MUTEX 0x01000000
107 ACPI_LV_THREADS 0x02000000
108 ACPI_LV_IO 0x04000000
109 ACPI_LV_INTERRUPTS 0x08000000
110 ACPI_LV_AML_DISASSEMBLE 0x10000000
111 ACPI_LV_VERBOSE_INFO 0x20000000
112 ACPI_LV_FULL_TABLES 0x40000000
113 ACPI_LV_EVENTS 0x80000000
114
115Examples
116--------
117
118For example, drivers/acpi/bus.c contains this:
119
120 #define _COMPONENT ACPI_BUS_COMPONENT
121 ...
122 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
123
124To turn on this message, set the ACPI_BUS_COMPONENT bit in acpi.debug_layer
125and the ACPI_LV_INFO bit in acpi.debug_level. (The ACPI_DEBUG_PRINT
126statement uses ACPI_DB_INFO, which is macro based on the ACPI_LV_INFO
127definition.)
128
129Enable all AML "Debug" output (stores to the Debug object while interpreting
130AML) during boot:
131
132 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
133
134Enable PCI and PCI interrupt routing debug messages:
135
136 acpi.debug_layer=0x400000 acpi.debug_level=0x4
137
138Enable all ACPI hardware-related messages:
139
140 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
141
142Enable all ACPI_DB_INFO messages after boot:
143
144 # echo 0x4 > /sys/module/acpi/parameters/debug_level
145
146Show all valid component values:
147
148 # cat /sys/module/acpi/parameters/debug_layer