On Tue, Nov 28, 2017 at 12:16:03PM +0100, Maarten Lankhorst wrote:

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")

Please use dim fixes to get a more complete Cc: list for regression fixes.

Cc: stable@vger.kernel.org # v4.14+ Reported-by: Thomas Voegtle tv@lio96.de

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

But please confirm with the reporter that it indeed fixes the issue before pushing. -Daniel

---

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

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 07374008f146..e56166334455 100644 --- 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(struct drm_fb_helper *fb_helper, 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; }

2.15.0