4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Ujfalusi <peter.ujfal...@ti.com>

commit 68f458eec7069d618a6c884ca007426e0cea411b upstream.

Instead of scheduling the work to handle the initial delayed event, use 1s
delay.

This delay should not be needed, but Optimus/nouveau will fail in a
mysterious way if the delayed event is handled as soon as possible like it
is done in drm_helper_probe_single_connector_modes() in case the poll
was enabled before.

Reverting 339fd36238dd would give back the 10 sec (!) delay to handle the
delayed event. Adding 1sec delay to the poll_work is enough to work around
the issue in Optimus setups and gives shorter response on handling the
initial delayed event.

Fixes: 339fd36238dd ("drm: drm_probe_helper: Fix output_poll_work scheduling")
Signed-off-by: Peter Ujfalusi <peter.ujfal...@ti.com>
[danvet: Add FIXME to the comment to make it stick out more.]
Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
Link: 
http://patchwork.freedesktop.org/patch/msgid/20170109143158.21917-1-peter.ujfal...@ti.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/gpu/drm/drm_probe_helper.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -143,8 +143,18 @@ void drm_kms_helper_poll_enable_locked(s
        }
 
        if (dev->mode_config.delayed_event) {
+               /*
+                * FIXME:
+                *
+                * Use short (1s) delay to handle the initial delayed event.
+                * This delay should not be needed, but Optimus/nouveau will
+                * fail in a mysterious way if the delayed event is handled as
+                * soon as possible like it is done in
+                * drm_helper_probe_single_connector_modes() in case the poll
+                * was enabled before.
+                */
                poll = true;
-               delay = 0;
+               delay = HZ;
        }
 
        if (poll)


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