Patch "drm/exynos: Fix locking in the suspend/resume paths" has been added to the 4.13-stable tree

Patch "drm/exynos: Fix locking in the suspend/resume paths" has been added to the 4.13-stable tree

[gregkh]

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

    drm/exynos: Fix locking in the suspend/resume paths

to the 4.13-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-fix-locking-in-the-suspend-resume-paths.patch
and it can be found in the queue-4.13 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 5baf6bb0fd2388742a0846cc7bcacee6dec78235 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Thu, 14 Sep 2017 14:01:00 +0200
Subject: drm/exynos: Fix locking in the suspend/resume paths

From: Marek Szyprowski <m.szyprowski@samsung.com>

commit 5baf6bb0fd2388742a0846cc7bcacee6dec78235 upstream.

Commit 48a92916729b ("drm/exynos: use drm_for_each_connector_iter()")
replaced unsafe drm_for_each_connector() with drm_for_each_connector_iter()
and removed surrounding drm_modeset_lock calls. However, that lock was
there not only to protect unsafe drm_for_each_connector(), but it was also
required to be held by the dpms code which was called from the loop body.
This patch restores those drm_modeset_lock calls to fix broken suspend
and resume of Exynos DRM subsystem in v4.13 kernel.

Fixes: 48a92916729b ("drm/exynos: use drm_for_each_connector_iter()")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -176,6 +176,7 @@ static int exynos_drm_suspend(struct dev
 	if (pm_runtime_suspended(dev) || !drm_dev)
 		return 0;
 
+	drm_modeset_lock_all(drm_dev);
 	drm_connector_list_iter_begin(drm_dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
 		int old_dpms = connector->dpms;
@@ -187,6 +188,7 @@ static int exynos_drm_suspend(struct dev
 		connector->dpms = old_dpms;
 	}
 	drm_connector_list_iter_end(&conn_iter);
+	drm_modeset_unlock_all(drm_dev);
 
 	return 0;
 }
@@ -200,6 +202,7 @@ static int exynos_drm_resume(struct devi
 	if (pm_runtime_suspended(dev) || !drm_dev)
 		return 0;
 
+	drm_modeset_lock_all(drm_dev);
 	drm_connector_list_iter_begin(drm_dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
 		if (connector->funcs->dpms) {
@@ -210,6 +213,7 @@ static int exynos_drm_resume(struct devi
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
+	drm_modeset_unlock_all(drm_dev);
 
 	return 0;
 }


Patches currently in stable-queue which might be from m.szyprowski@samsung.com are

queue-4.13/drm-exynos-fix-locking-in-the-suspend-resume-paths.patch