linux/Documentation/firmware-guide/acpi/debug.rst
Rafael J. Wysocki 3aadd86e56 ACPI: Drop unused ACPI_*_COMPONENT definitions and update documentation
Drop the definitions of the following symbols:

 ACPI_SBS_COMPONENT
 ACPI_FAN_COMPONENT
 ACPI_CONTAINER_COMPONENT
 ACPI_MEMORY_DEVICE_COMPONENT

that are not used in a meaningful way any more and update the ACPI
debug documentation to avoid confusing users by making the impression
that the ACPICA debug can be used for anything other than ACPICA
itself, which is incorrect.

No functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
2021-03-08 16:55:28 +01:00

133 lines
4.8 KiB
ReStructuredText

.. SPDX-License-Identifier: GPL-2.0
====================
ACPI CA Debug Output
====================
The ACPI CA can generate debug output. This document describes how to use this
facility.
Compile-time configuration
==========================
The ACPI CA debug output is globally enabled by CONFIG_ACPI_DEBUG. If this
config option is not set, 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 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.
Reading /sys/module/acpi/parameters/debug_layer shows the supported mask values::
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
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/acpica/evxfevnt.c contains this::
#define _COMPONENT ACPI_EVENTS
...
ACPI_DEBUG_PRINT((ACPI_DB_INIT, "ACPI mode disabled\n"));
To turn on this message, set the ACPI_EVENTS bit in acpi.debug_layer
and the ACPI_LV_INIT bit in acpi.debug_level. (The ACPI_DEBUG_PRINT
statement uses ACPI_DB_INIT, which is a macro based on the ACPI_LV_INIT
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 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