ACPI / x86: boot: Don't setup SCI on HW-reduced platforms

As per note in 5.2.9 Fixed ACPI Description Table (FADT) chapter of ACPI
specification, on HW-reduced platforma OSPM should ignore fields related
to the ACPI HW register interface, one of which is SCI_INT.

Follow the spec and ignore any configuration done for interrupt line
defined by SCI_INT if FADT specifies a HW-reduced platform.

HW-reduced platforms will still be able to use SCI in case it provides
an override record in MADT table.

Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: andy-shev

arch/x86/kernel/acpi/boot.c

@@ -1209,8 +1209,9 @@ static int __init acpi_parse_madt_ioapic_entries(void)
 	/*
 	 * If BIOS did not supply an INT_SRC_OVR for the SCI
 	 * pretend we got one so we can set the SCI flags.
+	 * But ignore setting up SCI on hardware reduced platforms.
 	 */
-	if (acpi_sci_override_gsi == INVALID_ACPI_IRQ)
+	if (acpi_sci_override_gsi == INVALID_ACPI_IRQ && !acpi_gbl_reduced_hardware)
 		acpi_sci_ioapic_setup(acpi_gbl_FADT.sci_interrupt, 0, 0,
 				      acpi_gbl_FADT.sci_interrupt);