drm/nouveau/kms/nv50-: fix panel scaling

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>

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 9ac47fe..63425e2 100644 (file)
--- 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;