Documentation/acpi/debug.txt

   1                         ACPI Debug Output
   2
   3
   4 The ACPI CA, the Linux ACPI core, and some ACPI drivers can generate debug
   5 output.  This document describes how to use this facility.
   6
   7 Compile-time configuration
   8 --------------------------
   9
  10 ACPI debug output is globally enabled by CONFIG_ACPI_DEBUG.  If this config
  11 option is turned off, the debug messages are not even built into the
  12 kernel.
  13
  14 Boot- and run-time configuration
  15 --------------------------------
  16
  17 When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages
  18 you're interested in.  At boot-time, use the acpi.debug_layer and
  19 acpi.debug_level kernel command line options.  After boot, you can use the
  20 debug_layer and debug_level files in /sys/module/acpi/parameters/ to control
  21 the debug messages.
  22
  23 debug_layer (component)
  24 -----------------------
  25
  26 The "debug_layer" is a mask that selects components of interest, e.g., a
  27 specific driver or part of the ACPI interpreter.  To build the debug_layer
  28 bitmask, look for the "#define _COMPONENT" in an ACPI source file.
  29
  30 You can set the debug_layer mask at boot-time using the acpi.debug_layer
  31 command line argument, and you can change it after boot by writing values
  32 to /sys/module/acpi/parameters/debug_layer.
  33
  34 The possible components are defined in include/acpi/acoutput.h and
  35 include/acpi/acpi_drivers.h.  Reading /sys/module/acpi/parameters/debug_layer
  36 shows 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
  67 debug_level
  68 -----------
  69
  70 The "debug_level" is a mask that selects different types of messages, e.g.,
  71 those related to initialization, method execution, informational messages, etc.
  72 To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT()
  73 statement.
  74
  75 The ACPI interpreter uses several different levels, but the Linux
  76 ACPI core and ACPI drivers generally only use ACPI_LV_INFO.
  77
  78 You can set the debug_level mask at boot-time using the acpi.debug_level
  79 command line argument, and you can change it after boot by writing values
  80 to /sys/module/acpi/parameters/debug_level.
  81
  82 The possible levels are defined in include/acpi/acoutput.h.  Reading
  83 /sys/module/acpi/parameters/debug_level shows the supported mask values,
  84 currently 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
 115 Examples
 116 --------
 117
 118 For 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
 124 To turn on this message, set the ACPI_BUS_COMPONENT bit in acpi.debug_layer
 125 and the ACPI_LV_INFO bit in acpi.debug_level.  (The ACPI_DEBUG_PRINT
 126 statement uses ACPI_DB_INFO, which is macro based on the ACPI_LV_INFO
 127 definition.)
 128
 129 Enable all AML "Debug" output (stores to the Debug object while interpreting
 130 AML) during boot:
 131
 132     acpi.debug_layer=0xffffffff acpi.debug_level=0x2
 133
 134 Enable PCI and PCI interrupt routing debug messages:
 135
 136     acpi.debug_layer=0x400000 acpi.debug_level=0x4
 137
 138 Enable all ACPI hardware-related messages:
 139
 140     acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
 141
 142 Enable all ACPI_DB_INFO messages after boot:
 143
 144     # echo 0x4 > /sys/module/acpi/parameters/debug_level
 145
 146 Show all valid component values:
 147
 148     # cat /sys/module/acpi/parameters/debug_layer