From 52dd06506e9bbc2a37b352df7dfc5468f8da21fd Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Tue, 28 Nov 2017 12:16:03 +0100
Subject: [PATCH] drm/fb_helper: Disable all crtc's when initial setup fails.
Git-commit: 52dd06506e9bbc2a37b352df7dfc5468f8da21fd
Patch-mainline: v4.15-rc2
References: FATE#322643 bsc#1055900

Some drivers like i915 start with crtc's enabled, but with deferred
fbcon setup they were no longer disabled as part of fbdev setup.
Headless units could no longer enter pc3 state because the crtc was
still enabled.

Fix this by calling restore_fbdev_mode when we would have called
it otherwise once during initial fbdev setup.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: ca91a2758fce ("drm/fb-helper: Support deferred setup")
Cc: <stable@vger.kernel.org> # v4.14+
Reported-by: Thomas Voegtle <tv@lio96.de>
Tested-by: Thomas Voegtle <tv@lio96.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171128111603.62757-1-maarten.lankhorst@linux.intel.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_fb_helper.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1809,6 +1809,10 @@ static int drm_fb_helper_single_fb_probe
 
 	if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
 		DRM_INFO("Cannot find any crtc or sizes\n");
+
+		/* First time: disable all crtc's.. */
+		if (!fb_helper->deferred_setup && !READ_ONCE(fb_helper->dev->master))
+			restore_fbdev_mode(fb_helper);
 		return -EAGAIN;
 	}