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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Roskin <plroskin@gmail.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Ben Skeggs <bskeggs@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 052/114] drm/nouveau/fbcon: fix oops without fbdev emulation
Date:   Thu,  8 Nov 2018 13:51:07 -0800
Message-Id: <20181108215105.860896186@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

[ Upstream commit 4813766325374af6ed0b66879ba6a0bbb05c83b6 ]

This is similar to an earlier commit 52dfcc5ccfbb ("drm/nouveau: fix for
disabled fbdev emulation"), but protects all occurrences of helper.fbdev
in the source.

I see oops in nouveau_fbcon_accel_save_disable() called from
nouveau_fbcon_set_suspend_work() on Linux 3.13 when
CONFIG_DRM_FBDEV_EMULATION option is disabled.

Signed-off-by: Pavel Roskin <plroskin@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/nouveau/nouveau_fbcon.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index e40a1b07a014..343476d15726 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -235,7 +235,7 @@ void
 nouveau_fbcon_accel_save_disable(struct drm_device *dev)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
-	if (drm->fbcon) {
+	if (drm->fbcon && drm->fbcon->helper.fbdev) {
 		drm->fbcon->saved_flags = drm->fbcon->helper.fbdev->flags;
 		drm->fbcon->helper.fbdev->flags |= FBINFO_HWACCEL_DISABLED;
 	}
@@ -245,7 +245,7 @@ void
 nouveau_fbcon_accel_restore(struct drm_device *dev)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
-	if (drm->fbcon) {
+	if (drm->fbcon && drm->fbcon->helper.fbdev) {
 		drm->fbcon->helper.fbdev->flags = drm->fbcon->saved_flags;
 	}
 }
@@ -257,7 +257,8 @@ nouveau_fbcon_accel_fini(struct drm_device *dev)
 	struct nouveau_fbdev *fbcon = drm->fbcon;
 	if (fbcon && drm->channel) {
 		console_lock();
-		fbcon->helper.fbdev->flags |= FBINFO_HWACCEL_DISABLED;
+		if (fbcon->helper.fbdev)
+			fbcon->helper.fbdev->flags |= FBINFO_HWACCEL_DISABLED;
 		console_unlock();
 		nouveau_channel_idle(drm->channel);
 		nvif_object_fini(&fbcon->twod);
-- 
2.17.1