ACPI: fix 2.6.28 acpi.debug_level regression

acpi_early_init() was changed to over-write the cmdline param,
making it really inconvenient to set debug flags at boot-time.

Also,
This sets the default level to "info", which is what all the ACPI
drivers use.  So to enable messages from drivers, you only have to
supply the "layer" (a.k.a. "component").  For non-"info" ACPI core
and ACPI interpreter messages, you have to supply both level and
layer masks, as before.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e0f346d201ed..c9115c1b672c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -220,14 +220,17 @@ and is between 256 and 4096 characters. It is defined in the file
                         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.
+                        The debug_level mask defaults to "info".  See
+                        Documentation/acpi/debug.txt for more information about
+                        debug layers and levels.
 
+                        Enable processor driver info messages:
+                            acpi.debug_layer=0x20000000
+                        Enable PCI/PCI interrupt routing info messages:
+                            acpi.debug_layer=0x400000
                         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