From a39749b012757ca837b2409b2139ce979ac390b1 Mon Sep 17 00:00:00 2001
From: sborrill <sborrill@NetBSD.org>
Date: Tue, 30 Jun 2020 13:14:21 +0000
Subject: [PATCH] Only need to set brightness if reading the initial state
 fails to sync firmware and the driver. Avoids black screen at boot time.
 Thanks to jmcneill@

---
 sys/dev/acpi/acpi_display.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/dev/acpi/acpi_display.c b/sys/dev/acpi/acpi_display.c
index 8b0fdd7cd16a..4ef8884005ad 100644
--- a/sys/dev/acpi/acpi_display.c
+++ b/sys/dev/acpi/acpi_display.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: acpi_display.c,v 1.17 2020/04/28 11:02:37 jmcneill Exp $	*/
+/*	$NetBSD: acpi_display.c,v 1.18 2020/06/30 13:14:21 sborrill Exp $	*/
 
 /*-
  * Copyright (c) 2010 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_display.c,v 1.17 2020/04/28 11:02:37 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_display.c,v 1.18 2020/06/30 13:14:21 sborrill Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -647,8 +647,8 @@ acpidisp_out_attach(device_t parent, device_t self, void *aux)
 		 * Synchronize ACPI and driver brightness levels, and
 		 * check that brightness control is working.
 		 */
-		(void)acpidisp_get_brightness(osc, &bc->bc_current);
-		if (acpidisp_set_brightness(osc, bc->bc_current)) {
+		if (acpidisp_get_brightness(osc, &bc->bc_current) &&
+		    acpidisp_set_brightness(osc, bc->bc_current)) {
 			kmem_free(bc->bc_level,
 			    bc->bc_level_count * sizeof(*bc->bc_level));
 			kmem_free(bc, sizeof(*bc));