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| -rw-r--r-- | Documentation/acpi/debug.txt | 148 |
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diff --git a/Documentation/acpi/debug.txt b/Documentation/acpi/debug.txt new file mode 100644 index 000000000..65bf47c46 --- /dev/null +++ b/Documentation/acpi/debug.txt @@ -0,0 +1,148 @@ + ACPI Debug Output + + +The ACPI CA, the Linux ACPI core, and some ACPI drivers can generate debug +output. This document describes how to use this facility. + +Compile-time configuration +-------------------------- + +ACPI debug output is globally enabled by CONFIG_ACPI_DEBUG. If this config +option is turned off, the debug messages are not even built into the +kernel. + +Boot- and run-time configuration +-------------------------------- + +When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages +you're interested in. At boot-time, use the acpi.debug_layer and +acpi.debug_level kernel command line options. After boot, you can use the +debug_layer and debug_level files in /sys/module/acpi/parameters/ to control +the debug messages. + +debug_layer (component) +----------------------- + +The "debug_layer" is a mask that selects components of interest, e.g., a +specific driver or part of the ACPI interpreter. To build the debug_layer +bitmask, look for the "#define _COMPONENT" in an ACPI source file. + +You can set the debug_layer mask at boot-time using the acpi.debug_layer +command line argument, and you can change it after boot by writing values +to /sys/module/acpi/parameters/debug_layer. + +The possible components are defined in include/acpi/acoutput.h and +include/acpi/acpi_drivers.h. Reading /sys/module/acpi/parameters/debug_layer +shows the supported mask values, currently these: + + ACPI_UTILITIES 0x00000001 + ACPI_HARDWARE 0x00000002 + ACPI_EVENTS 0x00000004 + ACPI_TABLES 0x00000008 + ACPI_NAMESPACE 0x00000010 + ACPI_PARSER 0x00000020 + ACPI_DISPATCHER 0x00000040 + ACPI_EXECUTER 0x00000080 + ACPI_RESOURCES 0x00000100 + ACPI_CA_DEBUGGER 0x00000200 + ACPI_OS_SERVICES 0x00000400 + ACPI_CA_DISASSEMBLER 0x00000800 + ACPI_COMPILER 0x00001000 + ACPI_TOOLS 0x00002000 + ACPI_BUS_COMPONENT 0x00010000 + ACPI_AC_COMPONENT 0x00020000 + ACPI_BATTERY_COMPONENT 0x00040000 + ACPI_BUTTON_COMPONENT 0x00080000 + ACPI_SBS_COMPONENT 0x00100000 + ACPI_FAN_COMPONENT 0x00200000 + ACPI_PCI_COMPONENT 0x00400000 + ACPI_POWER_COMPONENT 0x00800000 + ACPI_CONTAINER_COMPONENT 0x01000000 + ACPI_SYSTEM_COMPONENT 0x02000000 + ACPI_THERMAL_COMPONENT 0x04000000 + ACPI_MEMORY_DEVICE_COMPONENT 0x08000000 + ACPI_VIDEO_COMPONENT 0x10000000 + ACPI_PROCESSOR_COMPONENT 0x20000000 + +debug_level +----------- + +The "debug_level" is a mask that selects different types of messages, e.g., +those related to initialization, method execution, informational messages, etc. +To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT() +statement. + +The ACPI interpreter uses several different levels, but the Linux +ACPI core and ACPI drivers generally only use ACPI_LV_INFO. + +You can set the debug_level mask at boot-time using the acpi.debug_level +command line argument, and you can change it after boot by writing values +to /sys/module/acpi/parameters/debug_level. + +The possible levels are defined in include/acpi/acoutput.h. Reading +/sys/module/acpi/parameters/debug_level shows the supported mask values, +currently these: + + ACPI_LV_INIT 0x00000001 + ACPI_LV_DEBUG_OBJECT 0x00000002 + ACPI_LV_INFO 0x00000004 + ACPI_LV_INIT_NAMES 0x00000020 + ACPI_LV_PARSE 0x00000040 + ACPI_LV_LOAD 0x00000080 + ACPI_LV_DISPATCH 0x00000100 + ACPI_LV_EXEC 0x00000200 + ACPI_LV_NAMES 0x00000400 + ACPI_LV_OPREGION 0x00000800 + ACPI_LV_BFIELD 0x00001000 + ACPI_LV_TABLES 0x00002000 + ACPI_LV_VALUES 0x00004000 + ACPI_LV_OBJECTS 0x00008000 + ACPI_LV_RESOURCES 0x00010000 + ACPI_LV_USER_REQUESTS 0x00020000 + ACPI_LV_PACKAGE 0x00040000 + ACPI_LV_ALLOCATIONS 0x00100000 + ACPI_LV_FUNCTIONS 0x00200000 + ACPI_LV_OPTIMIZATIONS 0x00400000 + ACPI_LV_MUTEX 0x01000000 + ACPI_LV_THREADS 0x02000000 + ACPI_LV_IO 0x04000000 + ACPI_LV_INTERRUPTS 0x08000000 + ACPI_LV_AML_DISASSEMBLE 0x10000000 + ACPI_LV_VERBOSE_INFO 0x20000000 + ACPI_LV_FULL_TABLES 0x40000000 + ACPI_LV_EVENTS 0x80000000 + +Examples +-------- + +For example, drivers/acpi/bus.c contains this: + + #define _COMPONENT ACPI_BUS_COMPONENT + ... + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n")); + +To turn on this message, set the ACPI_BUS_COMPONENT bit in acpi.debug_layer +and the ACPI_LV_INFO bit in acpi.debug_level. (The ACPI_DEBUG_PRINT +statement uses ACPI_DB_INFO, which is macro based on the ACPI_LV_INFO +definition.) + +Enable all AML "Debug" output (stores to the Debug object while interpreting +AML) during boot: + + acpi.debug_layer=0xffffffff acpi.debug_level=0x2 + +Enable PCI and PCI interrupt routing debug messages: + + acpi.debug_layer=0x400000 acpi.debug_level=0x4 + +Enable all ACPI hardware-related messages: + + acpi.debug_layer=0x2 acpi.debug_level=0xffffffff + +Enable all ACPI_DB_INFO messages after boot: + + # echo 0x4 > /sys/module/acpi/parameters/debug_level + +Show all valid component values: + + # cat /sys/module/acpi/parameters/debug_layer |