Patch "drm/exynos/decon5433: update shadow registers iff there are active windows" 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/exynos/decon5433: update shadow registers iff there are active windows

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-exynos-decon5433-update-shadow-registers-iff-there-are-active-windows.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 foo@baz Wed Dec  6 17:39:55 CET 2017
From: Andrzej Hajda <a.hajda@samsung.com>
Date: Mon, 9 Jan 2017 15:33:02 +0100
Subject: drm/exynos/decon5433: update shadow registers iff there are active windows

From: Andrzej Hajda <a.hajda@samsung.com>


[ Upstream commit f65a7c9cb3770ed4d3e7c57c66d7032689081b5e ]

Improper usage of DECON_UPDATE register leads to subtle errors.
If it set in decon_commit when there are no active windows it results
in slow registry updates - all subsequent shadow registry updates takes more
than full vblank. On the other side if it is not set when there are
active windows it results in garbage on the screen after suspend/resume of
FB console.

The patch hopefully fixes it.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/exynos/exynos5433_drm_decon.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
@@ -188,8 +188,6 @@ static void decon_commit(struct exynos_d
 
 	/* enable output and display signal */
 	decon_set_bits(ctx, DECON_VIDCON0, VIDCON0_ENVID | VIDCON0_ENVID_F, ~0);
-
-	decon_set_bits(ctx, DECON_UPDATE, STANDALONE_UPDATE_F, ~0);
 }
 
 static void decon_win_set_pixfmt(struct decon_context *ctx, unsigned int win,
@@ -340,8 +338,9 @@ static void decon_atomic_flush(struct ex
 	for (i = ctx->first_win; i < WINDOWS_NR; i++)
 		decon_shadow_protect_win(ctx, i, false);
 
-	/* standalone update */
-	decon_set_bits(ctx, DECON_UPDATE, STANDALONE_UPDATE_F, ~0);
+	/* update iff there are active windows */
+	if (crtc->base.state->plane_mask)
+		decon_set_bits(ctx, DECON_UPDATE, STANDALONE_UPDATE_F, ~0);
 
 	if (ctx->out_type & IFTYPE_I80)
 		set_bit(BIT_WIN_UPDATED, &ctx->flags);


Patches currently in stable-queue which might be from a.hajda@samsung.com are

queue-4.9/drm-exynos-decon5433-set-standalone_update_f-also-if-planes-are-disabled.patch
queue-4.9/drm-exynos-decon5433-update-shadow-registers-iff-there-are-active-windows.patch
queue-4.9/drm-exynos-decon5433-set-standalone_update_f-on-output-enablement.patch