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>

1 files changed, 23 insertions, 52 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 343e0f0f84b6..e8951118deaf 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -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.
-
-        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.
-
-                        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.
+                        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.
+
+                        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
+
+                        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.