ACPI: Add S4BIOS support (Pavel Machek)

drivers/acpi/sleep/main.c

@@ -183,14 +183,21 @@ acpi_system_suspend(
 		status = acpi_enter_sleep_state(state);
 		break;
 
-	case ACPI_STATE_S2:
 #ifdef CONFIG_SOFTWARE_SUSPEND
+	case ACPI_STATE_S2:
 	case ACPI_STATE_S3:
 		do_suspend_lowlevel(0);
+		break;
 #endif
+	case ACPI_STATE_S4:
+		do_suspend_lowlevel_s4bios(0);
+		break;
+	default:
+		printk(KERN_WARNING PREFIX "don't know how to handle %d state.\n", state);
 		break;
 	}
 	local_irq_restore(flags);
+	printk(KERN_CRIT "Back to C!\n");
 
 	return status;
 }
@@ -211,10 +218,20 @@ acpi_suspend (
 	if (state < ACPI_STATE_S1 || state > ACPI_STATE_S5)
 		return AE_ERROR;
 
+	/* Since we handle S4OS via a different path (swsusp), give up if no s4bios. */
+	if (state == ACPI_STATE_S4 && !acpi_gbl_FACS->S4bios_f)
+		return AE_ERROR;
+
+	/*
+	 * TBD: S1 can be done without device_suspend.  Make a CONFIG_XX
+	 * to handle however when S1 failed without device_suspend.
+	 */
 	freeze_processes();		/* device_suspend needs processes to be stopped */
 
 	/* do we have a wakeup address for S2 and S3? */
-	if (state == ACPI_STATE_S2 || state == ACPI_STATE_S3) {
+	/* Here, we support only S4BIOS, those we set the wakeup address */
+	/* S4OS is only supported for now via swsusp.. */
+	if (state == ACPI_STATE_S2 || state == ACPI_STATE_S3 || ACPI_STATE_S4) {
 		if (!acpi_wakeup_address)
 			return AE_ERROR;
 		acpi_set_firmware_waking_vector((acpi_physical_address) acpi_wakeup_address);
@@ -268,6 +285,10 @@ static int __init acpi_sleep_init(void)
 			sleep_states[i] = 1;
 			printk(" S%d", i);
 		}
+		if (i == ACPI_STATE_S4 && acpi_gbl_FACS->S4bios_f) {
+			sleep_states[i] = 1;
+			printk(" S4bios");
+		}
 	}
 	printk(")\n");
 

drivers/acpi/sleep/proc.c

@@ -27,8 +27,11 @@ static int acpi_system_sleep_seq_show(struct seq_file *seq, void *offset)
 	ACPI_FUNCTION_TRACE("acpi_system_sleep_seq_show");
 
 	for (i = 0; i <= ACPI_STATE_S5; i++) {
-		if (sleep_states[i])
+		if (sleep_states[i]) {
 			seq_printf(seq,"S%d ", i);
+			if (i == ACPI_STATE_S4 && acpi_gbl_FACS->S4bios_f)
+				seq_printf(seq, "S4bios ");
+		}
 	}
 
 	seq_puts(seq, "\n");

include/linux/suspend.h

@@ -73,6 +73,7 @@ extern void do_magic_suspend_2(void);
 /* Communication between acpi and arch/i386/suspend.c */
 
 extern void do_suspend_lowlevel(int resume);
+extern void do_suspend_lowlevel_s4bios(int resume);
 
 #else
 static inline void software_suspend(void)