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, 7 insertions, 3 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 90cb2a823b56..b0243fd55ac0 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -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"