This is a note to let you know that I've just added the patch titled

drm/fb_helper: Disable all crtc's when initial setup fails.

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: drm-fb_helper-disable-all-crtc-s-when-initial-setup-fails.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

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: drm/fb_helper: Disable all crtc's when initial setup fails.

From: Maarten Lankhorst maarten.lankhorst@linux.intel.com

commit 52dd06506e9bbc2a37b352df7dfc5468f8da21fd upstream.

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") 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... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- 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; }

Patches currently in stable-queue which might be from maarten.lankhorst@linux.intel.com are

queue-4.14/drm-fb_helper-disable-all-crtc-s-when-initial-setup-fails.patch