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 149