| .. SPDX-License-Identifier: GPL-2.0 |
| |
| ================= |
| 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 |
