4.14-stable review patch. If anyone has any objections, please let me know.
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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; }