ACPI: Allow setting SCI_EN bit in PM1_CONTROL register

This is needed by at least the Mac Mini's, which (incorrectly) come back
from suspend with SCI_EN clear.

Thanks to Frdric Riss for hunting this down.
Acked-by: NFrdric Riss <frederic.riss@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/acpi/hardware/hwregs.c

@@ -665,8 +665,6 @@ acpi_status acpi_hw_register_write(u8 use_lock, u32 register_id, u32 value)
 
 		/*
 		 * Perform a read first to preserve certain bits (per ACPI spec)
-		 *
-		 * Note: This includes SCI_EN, we never want to change this bit
 		 */
 		status = acpi_hw_register_read(ACPI_MTX_DO_NOT_LOCK,
 					       ACPI_REGISTER_PM1_CONTROL,

include/acpi/aclocal.h

@@ -708,7 +708,7 @@ struct acpi_bit_register_info {
  * must be preserved.
  */
 #define ACPI_PM1_STATUS_PRESERVED_BITS          0x0800	/* Bit 11 */
-#define ACPI_PM1_CONTROL_PRESERVED_BITS         0x0201	/* Bit 9, Bit 0 (SCI_EN) */
+#define ACPI_PM1_CONTROL_PRESERVED_BITS         0x0200	/* Bit 9 (whatever) */
 
 /*
  * Register IDs