133 lines
4.8 KiB
ReStructuredText
133 lines
4.8 KiB
ReStructuredText
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.. SPDX-License-Identifier: GPL-2.0
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====================
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ACPI CA Debug Output
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====================
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The ACPI CA can generate debug output. This document describes how to use this
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facility.
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Compile-time configuration
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==========================
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The ACPI CA debug output is globally enabled by CONFIG_ACPI_DEBUG. If this
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config option is not set, the debug messages are not even built into the kernel.
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Boot- and run-time configuration
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================================
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When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages
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you're interested in. At boot-time, use the acpi.debug_layer and
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acpi.debug_level kernel command line options. After boot, you can use the
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debug_layer and debug_level files in /sys/module/acpi/parameters/ to control
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the debug messages.
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debug_layer (component)
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=======================
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The "debug_layer" is a mask that selects components of interest, e.g., a
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specific part of the ACPI interpreter. To build the debug_layer bitmask, look
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for the "#define _COMPONENT" in an ACPI source file.
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You can set the debug_layer mask at boot-time using the acpi.debug_layer
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command line argument, and you can change it after boot by writing values
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to /sys/module/acpi/parameters/debug_layer.
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The possible components are defined in include/acpi/acoutput.h.
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Reading /sys/module/acpi/parameters/debug_layer shows the supported mask values::
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ACPI_UTILITIES 0x00000001
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ACPI_HARDWARE 0x00000002
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ACPI_EVENTS 0x00000004
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ACPI_TABLES 0x00000008
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ACPI_NAMESPACE 0x00000010
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ACPI_PARSER 0x00000020
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ACPI_DISPATCHER 0x00000040
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ACPI_EXECUTER 0x00000080
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ACPI_RESOURCES 0x00000100
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ACPI_CA_DEBUGGER 0x00000200
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ACPI_OS_SERVICES 0x00000400
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ACPI_CA_DISASSEMBLER 0x00000800
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ACPI_COMPILER 0x00001000
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ACPI_TOOLS 0x00002000
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debug_level
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===========
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The "debug_level" is a mask that selects different types of messages, e.g.,
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those related to initialization, method execution, informational messages, etc.
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To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT()
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statement.
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The ACPI interpreter uses several different levels, but the Linux
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ACPI core and ACPI drivers generally only use ACPI_LV_INFO.
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You can set the debug_level mask at boot-time using the acpi.debug_level
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command line argument, and you can change it after boot by writing values
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to /sys/module/acpi/parameters/debug_level.
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The possible levels are defined in include/acpi/acoutput.h. Reading
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/sys/module/acpi/parameters/debug_level shows the supported mask values,
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currently these::
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ACPI_LV_INIT 0x00000001
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ACPI_LV_DEBUG_OBJECT 0x00000002
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ACPI_LV_INFO 0x00000004
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ACPI_LV_INIT_NAMES 0x00000020
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ACPI_LV_PARSE 0x00000040
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ACPI_LV_LOAD 0x00000080
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ACPI_LV_DISPATCH 0x00000100
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ACPI_LV_EXEC 0x00000200
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ACPI_LV_NAMES 0x00000400
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ACPI_LV_OPREGION 0x00000800
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ACPI_LV_BFIELD 0x00001000
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ACPI_LV_TABLES 0x00002000
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ACPI_LV_VALUES 0x00004000
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ACPI_LV_OBJECTS 0x00008000
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ACPI_LV_RESOURCES 0x00010000
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ACPI_LV_USER_REQUESTS 0x00020000
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ACPI_LV_PACKAGE 0x00040000
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ACPI_LV_ALLOCATIONS 0x00100000
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ACPI_LV_FUNCTIONS 0x00200000
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ACPI_LV_OPTIMIZATIONS 0x00400000
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ACPI_LV_MUTEX 0x01000000
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ACPI_LV_THREADS 0x02000000
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ACPI_LV_IO 0x04000000
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ACPI_LV_INTERRUPTS 0x08000000
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ACPI_LV_AML_DISASSEMBLE 0x10000000
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ACPI_LV_VERBOSE_INFO 0x20000000
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ACPI_LV_FULL_TABLES 0x40000000
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ACPI_LV_EVENTS 0x80000000
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Examples
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========
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For example, drivers/acpi/acpica/evxfevnt.c contains this::
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#define _COMPONENT ACPI_EVENTS
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...
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ACPI_DEBUG_PRINT((ACPI_DB_INIT, "ACPI mode disabled\n"));
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To turn on this message, set the ACPI_EVENTS bit in acpi.debug_layer
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and the ACPI_LV_INIT bit in acpi.debug_level. (The ACPI_DEBUG_PRINT
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statement uses ACPI_DB_INIT, which is a macro based on the ACPI_LV_INIT
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definition.)
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Enable all AML "Debug" output (stores to the Debug object while interpreting
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AML) during boot::
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acpi.debug_layer=0xffffffff acpi.debug_level=0x2
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Enable all ACPI hardware-related messages::
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acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
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Enable all ACPI_DB_INFO messages after boot::
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# echo 0x4 > /sys/module/acpi/parameters/debug_level
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Show all valid component values::
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# cat /sys/module/acpi/parameters/debug_layer
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