[PATCH v1 06/27] ACPICA: Fix FADT 32/64X length mismatch warning

["Rafael J. Wysocki" <rafael@kernel.org>]

From: Abdelkader Boudih <oss@seuros.com>

When the 64-bit address is set but bit_width is 0, the spec says
the legacy length should be used. That is valid firmware.

Skip the warning if bit_width is 0.

This avoids false warnings like:
  32/64X length mismatch in FADT/gpe0_block: 128/0

Tested on free_BSD 16.0-CURRENT.

Link: https://github.com/acpica/acpica/commit/b6387a387c51
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpica/tbfadt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index c6658b2f3027..80d3a39a82d7 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -553,8 +553,11 @@ static void acpi_tb_convert_fadt(void)
 				 * Note: If the legacy length field is > 0xFF bits, ignore
 				 * this check. (GPE registers can be larger than the
 				 * 64-bit GAS structure can accommodate, 0xFF bits).
+				 * Also skip if bit_width is 0, indicating the 64-bit field
+				 * was not populated - legacy length will be used instead.
 				 */
 				if ((ACPI_MUL_8(length) <= ACPI_UINT8_MAX) &&
+				    (address64->bit_width != 0) &&
 				    (address64->bit_width !=
 				     ACPI_MUL_8(length))) {
 					ACPI_BIOS_WARNING((AE_INFO,
-- 
2.51.0