ACPICA: Tables: Avoid SSDT installation with acpi_gbl_disable_ssdt_table_load.

It is reported that when acpi_gbl_disable_ssdt_table_load is specified, user
still can see it installed into /sys/firmware/acpi/tables on Linux boxes.
This is because the option only stops table "loading", but doesn't stop
table "installing", thus it is still in the acpi_gbl_root_table_list. With
previous cleanups, it is possible to prevent SSDT installations to make
it not such confusing.  The global variable is also renamed.  Lv Zheng.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
index cf1ccc576629..de10d3245d9c 100644
--- a/drivers/acpi/acpica/tbinstal.c
+++ b/drivers/acpi/acpica/tbinstal.c
@@ -580,6 +580,18 @@ acpi_tb_install_non_fixed_table(acpi_physical_address address,
 		return_ACPI_STATUS(status);
 	}
 
+	/*
+	 * Optionally do not load any SSDTs from the RSDT/XSDT. This can
+	 * be useful for debugging ACPI problems on some machines.
+	 */
+	if (!reload && acpi_gbl_disable_ssdt_table_install &&
+	    ACPI_COMPARE_NAME(&new_table_desc.signature, ACPI_SIG_SSDT)) {
+		ACPI_INFO((AE_INFO, "Ignoring installation of %4.4s at %p",
+			   new_table_desc.signature.ascii, ACPI_CAST_PTR(void,
+									 address)));
+		goto release_and_exit;
+	}
+
 	/* Validate and verify a table before installation */
 
 	status = acpi_tb_verify_table(&new_table_desc, NULL);