From 3d1890ef8023e61934e070021b06cc9f417260c0 Mon Sep 17 00:00:00 2001
From: Ben Skeggs <bskeggs@redhat.com>
Date: Tue, 10 Dec 2019 12:15:44 +1000
Subject: drm/nouveau/kms/nv50-: fix panel scaling
Git-commit: 3d1890ef8023e61934e070021b06cc9f417260c0
Patch-mainline: v5.5-rc2
References: bsc#1152472

Under certain circumstances, encoder atomic_check() can be entered
without adjusted_mode having been reset to the same as mode, which
confuses the scaling logic and can lead to a misprogrammed display.

Fix this by checking against the user-provided mode directly.

Link: https://bugs.freedesktop.org/show_bug.cgi?id=108615
Link: https://gitlab.freedesktop.org/xorg/driver/xf86-video-nouveau/issues/464
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 9ac47fe519f8..63425e246018 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -326,9 +326,9 @@ nv50_outp_atomic_check_view(struct drm_encoder *encoder,
 			 * same size as the native one (e.g. different
 			 * refresh rate)
 			 */
-			if (adjusted_mode->hdisplay == native_mode->hdisplay &&
-			    adjusted_mode->vdisplay == native_mode->vdisplay &&
-			    adjusted_mode->type & DRM_MODE_TYPE_DRIVER)
+			if (mode->hdisplay == native_mode->hdisplay &&
+			    mode->vdisplay == native_mode->vdisplay &&
+			    mode->type & DRM_MODE_TYPE_DRIVER)
 				break;
 			mode = native_mode;
 			asyc->scaler.full = true;
-- 
2.28.0