[PATCH 2/4] ACPI / x86: Pass the constraints checking result to LPS0 callback

[Mario Limonciello <mario.limonciello@xxxxxxx>]

If constraints checking has been enabled by the LPS0 code, it may
also be useful for drivers using the callback to make a decision what
to do.

For example this may in the future allow a failing constraints check
preventing another driver from notifying firmware that all required
devices have entered the deepest state.

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
 drivers/acpi/x86/s2idle.c | 17 ++++++++++-------
 include/linux/acpi.h      |  4 ++--
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index 652dc2d75458..c737a8e5d5a5 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -88,7 +88,7 @@ struct lpi_device_constraint_amd {
 
 struct lps0_callback_handler {
 	struct list_head list_node;
-	int (*prepare_late_callback)(void *context);
+	int (*prepare_late_callback)(void *context, bool constraints);
 	void (*restore_early_callback)(void *context);
 	void *context;
 };
@@ -297,7 +297,7 @@ static void lpi_device_get_constraints(void)
 	ACPI_FREE(out_obj);
 }
 
-static void lpi_check_constraints(void)
+static void lpi_check_constraints(bool *met)
 {
 	int i;
 
@@ -319,11 +319,13 @@ static void lpi_check_constraints(void)
 			continue;
 		}
 
-		if (adev->power.state < lpi_constraints_table[i].min_dstate)
+		if (adev->power.state < lpi_constraints_table[i].min_dstate) {
 			acpi_handle_info(handle,
 				"LPI: Constraint not met; min power state:%s current power state:%s\n",
 				acpi_power_state_string(lpi_constraints_table[i].min_dstate),
 				acpi_power_state_string(adev->power.state));
+			*met = false;
+		}
 	}
 }
 
@@ -455,13 +457,14 @@ static struct acpi_scan_handler lps0_handler = {
 int acpi_s2idle_prepare_late(void)
 {
 	struct lps0_callback_handler *handler;
+	bool constraints_met = true;
 	int rc = 0;
 
 	if (!lps0_device_handle || sleep_no_lps0)
 		return 0;
 
 	if (pm_debug_messages_on)
-		lpi_check_constraints();
+		lpi_check_constraints(&constraints_met);
 
 	/* Screen off */
 	if (lps0_dsm_func_mask > 0)
@@ -490,7 +493,7 @@ int acpi_s2idle_prepare_late(void)
 
 	mutex_lock(&lps0_callback_handler_mutex);
 	list_for_each_entry(handler, &lps0_callback_handler_head, list_node) {
-		rc = handler->prepare_late_callback(handler->context);
+		rc = handler->prepare_late_callback(handler->context, constraints_met);
 		if (rc)
 			goto out;
 	}
@@ -554,7 +557,7 @@ void acpi_s2idle_setup(void)
 	s2idle_set_ops(&acpi_s2idle_ops_lps0);
 }
 
-int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
+int acpi_register_lps0_callbacks(int (*prepare_late)(void *context, bool constraints),
 				 void (*restore_early)(void *context),
 				 void *context)
 {
@@ -578,7 +581,7 @@ int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
 }
 EXPORT_SYMBOL_GPL(acpi_register_lps0_callbacks);
 
-void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
+void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context, bool constraints),
 				    void (*restore_early)(void *context),
 				    void *context)
 {
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index cae0fde309f2..5aae774670dc 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1024,10 +1024,10 @@ void acpi_os_set_prepare_extended_sleep(int (*func)(u8 sleep_state,
 acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
 					   u32 val_a, u32 val_b);
 #ifdef CONFIG_X86
-int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
+int acpi_register_lps0_callbacks(int (*prepare_late)(void *context, bool constraints),
 				 void (*restore_early)(void *context),
 				 void *context);
-void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
+void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context, bool constraints),
 				    void (*restore_early)(void *context),
 				    void *context);
 #endif /* CONFIG_X86 */
-- 
2.34.1