[PATCH v2 2/5] ACPI / x86: Pass the constraints checking result to LPS0 callback

[Mario Limonciello <mario.limonciello@amd.com>]

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@amd.com>
---
Changes from v1->v2:
 * rebase on top of changes in first patch

 drivers/acpi/x86/s2idle.c | 11 +++++++----
 include/linux/acpi.h      |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index 7418443580d4..808018bbab90 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -290,7 +290,7 @@ 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;
 
@@ -312,11 +312,13 @@ 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;
+		}
 	}
 }
 
@@ -448,13 +450,14 @@ 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)
@@ -483,7 +486,7 @@ 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;
 	}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index df105f5e03e5..4906db854554 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1026,7 +1026,7 @@ acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
 #ifdef CONFIG_X86
 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;
 };
-- 
2.34.1