ACPI: x86: Add pm_debug_messages for LPS0 _DSM state tracking

Enabling debugging messages for the state requires turning on dynamic
debugging for the file. To make it more accessible, use
`pm_debug_messages` and clearer strings for what is happening.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/x86/s2idle.c

@@ -59,6 +59,7 @@ static int lps0_dsm_func_mask;
 
 static guid_t lps0_dsm_guid_microsoft;
 static int lps0_dsm_func_mask_microsoft;
+static int lps0_dsm_state;
 
 /* Device constraint entry structure */
 struct lpi_device_info {
@@ -320,6 +321,44 @@ static void lpi_check_constraints(void)
 	}
 }
 
+static bool acpi_s2idle_vendor_amd(void)
+{
+	return boot_cpu_data.x86_vendor == X86_VENDOR_AMD;
+}
+
+static const char *acpi_sleep_dsm_state_to_str(unsigned int state)
+{
+	if (lps0_dsm_func_mask_microsoft || !acpi_s2idle_vendor_amd()) {
+		switch (state) {
+		case ACPI_LPS0_SCREEN_OFF:
+			return "screen off";
+		case ACPI_LPS0_SCREEN_ON:
+			return "screen on";
+		case ACPI_LPS0_ENTRY:
+			return "lps0 entry";
+		case ACPI_LPS0_EXIT:
+			return "lps0 exit";
+		case ACPI_LPS0_MS_ENTRY:
+			return "lps0 ms entry";
+		case ACPI_LPS0_MS_EXIT:
+			return "lps0 ms exit";
+		}
+	} else {
+		switch (state) {
+		case ACPI_LPS0_SCREEN_ON_AMD:
+			return "screen on";
+		case ACPI_LPS0_SCREEN_OFF_AMD:
+			return "screen off";
+		case ACPI_LPS0_ENTRY_AMD:
+			return "lps0 entry";
+		case ACPI_LPS0_EXIT_AMD:
+			return "lps0 exit";
+		}
+	}
+
+	return "unknown";
+}
+
 static void acpi_sleep_run_lps0_dsm(unsigned int func, unsigned int func_mask, guid_t dsm_guid)
 {
 	union acpi_object *out_obj;
@@ -331,14 +370,15 @@ static void acpi_sleep_run_lps0_dsm(unsigned int func, unsigned int func_mask, g
 					rev_id, func, NULL);
 	ACPI_FREE(out_obj);
 
-	acpi_handle_debug(lps0_device_handle, "_DSM function %u evaluation %s\n",
-			  func, out_obj ? "successful" : "failed");
+	lps0_dsm_state = func;
+	if (pm_debug_messages_on) {
+		acpi_handle_info(lps0_device_handle,
+				"%s transitioned to state %s\n",
+				 out_obj ? "Successfully" : "Failed to",
+				 acpi_sleep_dsm_state_to_str(lps0_dsm_state));
+	}
 }
 
-static bool acpi_s2idle_vendor_amd(void)
-{
-	return boot_cpu_data.x86_vendor == X86_VENDOR_AMD;
-}
 
 static int validate_dsm(acpi_handle handle, const char *uuid, int rev, guid_t *dsm_guid)
 {