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ACPI: update debug parameter documentation 

Reformat acpi.debug_layer and acpi.debug_level documentation so it's
more readable, add some clues about how to figure out the mask bits that
enable a specific ACPI_DEBUG_PRINT statement, and include some useful
examples.

Move the list of masks to Documentation/acpi/debug.txt (these are
copies of the authoritative values in acoutput.h and acpi_drivers.h).

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Bjorn Helgaas 2008-11-07 16:58:05 -07:00 committed by Len Brown
parent 87b586088e
commit a0d84a92df
3 changed files with 176 additions and 53 deletions
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148
Documentation/acpi/debug.txt Normal file
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@ -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

71
Documentation/kernel-parameters.txt
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@ -198,59 +198,30 @@ and is between 256 and 4096 characters. It is defined in the file
that require a timer override, but don't have
HPET
acpi.debug_layer= [HW,ACPI]
acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Format: <int>
Each bit of the <int> indicates an ACPI debug layer,
1: enable, 0: disable. It is useful for boot time
debugging. After system has booted up, it can be set
via /sys/module/acpi/parameters/debug_layer.
CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
Available bits (add the numbers together) to enable debug output
for specific parts of the ACPI subsystem:
0x01 utilities 0x02 hardware 0x04 events 0x08 tables
0x10 namespace 0x20 parser 0x40 dispatcher
0x80 executer 0x100 resources 0x200 acpica debugger
0x400 os services 0x800 acpica disassembler.
The number can be in decimal or prefixed with 0x in hex.
Warning: Many of these options can produce a lot of
output and make your system unusable. Be very careful.
CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
debug output. Bits in debug_layer correspond to a
_COMPONENT in an ACPI source file, e.g.,
#define _COMPONENT ACPI_PCI_COMPONENT
Bits in debug_level correspond to a level in
ACPI_DEBUG_PRINT statements, e.g.,
ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
See Documentation/acpi/debug.txt for more information
about debug layers and levels.
acpi.debug_level= [HW,ACPI]
Format: <int>
Each bit of the <int> indicates an ACPI debug level,
which corresponds to the level in an ACPI_DEBUG_PRINT
statement. After system has booted up, this mask
can be set via /sys/module/acpi/parameters/debug_level.
Enable AML "Debug" output, i.e., stores to the Debug
object while interpreting AML:
acpi.debug_layer=0xffffffff acpi.debug_level=0x2
Enable PCI/PCI interrupt routing info messages:
acpi.debug_layer=0x400000 acpi.debug_level=0x4
Enable all messages related to ACPI hardware:
acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
CONFIG_ACPI_DEBUG must be enabled for this to produce
any output. The number can be in decimal or prefixed
with 0x in hex. Some of these options produce so much
output that the system is unusable.
The following global components are defined by the
ACPI CA:
0x01 error
0x02 warn
0x04 init
0x08 debug object
0x10 info
0x20 init names
0x40 parse
0x80 load
0x100 dispatch
0x200 execute
0x400 names
0x800 operation region
0x1000 bfield
0x2000 tables
0x4000 values
0x8000 objects
0x10000 resources
0x20000 user requests
0x40000 package
The number can be in decimal or prefixed with 0x in hex.
Warning: Many of these options can produce a lot of
output and make your system unusable. Be very careful.
Some values produce so much output that the system is
unusable. The "log_buf_len" parameter may be useful
if you need to capture more output.
acpi.power_nocheck= [HW,ACPI]
Format: 1/0 enable/disable the check of power state.

10
drivers/acpi/Kconfig
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@ -312,9 +312,13 @@ config ACPI_DEBUG
bool "Debug Statements"
default n
help
The ACPI driver can optionally report errors with a great deal
of verbosity. Saying Y enables these statements. This will increase
your kernel size by around 50K.
The ACPI subsystem can produce debug output. Saying Y enables this
output and increases the kernel size by around 50K.
Use the acpi.debug_layer and acpi.debug_level kernel command-line
parameters documented in Documentation/acpi/debug.txt and
Documentation/kernel-parameters.txt to control the type and
amount of debug output.
config ACPI_DEBUG_FUNC_TRACE
bool "Additionally enable ACPI function tracing"