src: Never overwrite `fadt->flags`
Instead, just flip the desired bits using bitwise operations. As this is
initially zero, the resulting value is the same. This allows flags to be
set from anywhere regardless of execution order.
Tested on Asus P8Z77-V LX2 with Linux 5.7.6 and Windows 10 at the end of
the patch train, both operating systems are able to boot successfully.
Change-Id: Icfd580a20524936cd0adac574331b09fb2aea925
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43387
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/southbridge/amd/cimx/sb800/fadt.c b/src/southbridge/amd/cimx/sb800/fadt.c
index c96d713..5f31cd5 100644
--- a/src/southbridge/amd/cimx/sb800/fadt.c
+++ b/src/southbridge/amd/cimx/sb800/fadt.c
@@ -81,7 +81,7 @@
fadt->century = 0; /* 0x7f to make rtc alarm work */
fadt->iapc_boot_arch = FADT_BOOT_ARCH; /* See table 5-10 */
fadt->res2 = 0; /* reserved, MUST be 0 ACPI 3.0 */
- fadt->flags = ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
+ fadt->flags |= ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
ACPI_FADT_C1_SUPPORTED |
ACPI_FADT_SLEEP_BUTTON |
ACPI_FADT_S4_RTC_WAKE |