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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, Ben Skeggs <bskeggs@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 038/191] drm/nouveau/kms/nv50-: fix panel scaling
Date:   Tue,  7 Jan 2020 21:52:38 +0100
Message-Id: <20200107205335.035106704@linuxfoundation.org>
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From: Ben Skeggs <bskeggs@redhat.com>

[ Upstream commit 3d1890ef8023e61934e070021b06cc9f417260c0 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 b5b1a34f896f..d735ea7e2d88 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;
-- 
2.20.1