ACPI: PRM: Find PRMT table before parsing it

Find and verify PRMT before parsing it, which eliminates a
warning on machines without PRMT:

	[    7.197173] ACPI: PRMT not present

Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: 5.14+ <stable@vger.kernel.org> # 5.14+
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index 1f6007abcf18eda3259ae274d08a6b1f48cc5dde..89c22bc550570d2bdb448ca0dca5b251e58618e5 100644 (file)
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -288,10 +288,18 @@ invalid_guid:
 
 void __init init_prmt(void)
 {
+       struct acpi_table_header *tbl;
        acpi_status status;
-       int mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
+       int mc;
+
+       status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
+       if (ACPI_FAILURE(status))
+               return;
+
+       mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
                                          sizeof (struct acpi_table_prmt_header),
                                          0, acpi_parse_prmt, 0);
+       acpi_put_table(tbl);
        /*
         * Return immediately if PRMT table is not present or no PRM module found.
         */