x86: acpi: Let OS know that console already had been initialized

[oweals/u-boot.git] / arch / x86 / lib / acpi_table.c

diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 66e32f21bdbd84643bcabbe8dc77d515ed91a917..074987e29433929b49c8339ca2fd235a3c6cf91c 100644 (file)
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -471,6 +471,15 @@ static void acpi_create_spcr(struct acpi_spcr *spcr)
        spcr->pci_device_id = 0xffff;
        spcr->pci_vendor_id = 0xffff;
 
+       /*
+        * SPCR has no clue if the UART base clock speed is different
+        * to the default one. However, the SPCR 1.04 defines baud rate
+        * 0 as a preconfigured state of UART and OS is supposed not
+        * to touch the configuration of the serial device.
+        */
+       if (serial_info.clock != SERIAL_DEFAULT_CLOCK)
+               spcr->baud_rate = 0;
+
        /* Fix checksum */
        header->checksum = table_compute_checksum((void *)spcr, header->length);
 }