Patch "drm: Schedule the output_poll_work with 1s delay if we have delayed event" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    drm: Schedule the output_poll_work with 1s delay if we have delayed event

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-schedule-the-output_poll_work-with-1s-delay-if-we-have-delayed-event.patch
and it can be found in the queue-4.9 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 68f458eec7069d618a6c884ca007426e0cea411b Mon Sep 17 00:00:00 2001
From: Peter Ujfalusi <peter.ujfalusi@ti.com>
Date: Mon, 9 Jan 2017 16:31:58 +0200
Subject: drm: Schedule the output_poll_work with 1s delay if we have delayed event

From: Peter Ujfalusi <peter.ujfalusi@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.ujfalusi@ti.com>
[danvet: Add FIXME to the comment to make it stick out more.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170109143158.21917-1-peter.ujfalusi@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@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)


Patches currently in stable-queue which might be from peter.ujfalusi@ti.com are

queue-4.9/drm-schedule-the-output_poll_work-with-1s-delay-if-we-have-delayed-event.patch