ACPICA: Add a comment, no functional change

ACPICA commit d586c29a026a6172c1113df4d75fd6d764196e77

Describe 2nd byte of the end_tag resource descriptor.

Link: https://github.com/acpica/acpica/commit/d586c29a
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/utresrc.c b/drivers/acpi/acpica/utresrc.c
index d955bf852a037e104235d77d5b0610af3f15e724..517acf8e77c8042ed62be801801c152458df5e2b 100644 (file)
--- a/drivers/acpi/acpica/utresrc.c
+++ b/drivers/acpi/acpica/utresrc.c
@@ -239,6 +239,13 @@ acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
                                return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
                        }
 
+                       /*
+                        * Don't attempt to perform any validation on the 2nd byte.
+                        * Although all known ASL compilers insert a zero for the 2nd
+                        * byte, it can also be a checksum (as per the ACPI spec),
+                        * and this is occasionally seen in the field. July 2017.
+                        */
+
                        /* Return the pointer to the end_tag if requested */
 
                        if (!user_function) {