drm: Add drm_mode_copy()

Add a helper function to copy a display mode. Use it in
drm_mode_duplicate() and nouveau mode_fixup hooks.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_modes.c

@@ -713,6 +713,27 @@ void drm_mode_set_crtcinfo(struct drm_display_mode *p, int adjust_flags)
 EXPORT_SYMBOL(drm_mode_set_crtcinfo);
 
 
+/**
+ * drm_mode_copy - copy the mode
+ * @dst: mode to overwrite
+ * @src: mode to copy
+ *
+ * LOCKING:
+ * None.
+ *
+ * Copy an existing mode into another mode, preserving the object id
+ * of the destination mode.
+ */
+void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode *src)
+{
+	int id = dst->base.id;
+
+	*dst = *src;
+	dst->base.id = id;
+	INIT_LIST_HEAD(&dst->head);
+}
+EXPORT_SYMBOL(drm_mode_copy);
+
 /**
  * drm_mode_duplicate - allocate and duplicate an existing mode
  * @m: mode to duplicate
@@ -727,16 +748,13 @@ struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
 					    const struct drm_display_mode *mode)
 {
 	struct drm_display_mode *nmode;
-	int new_id;
 
 	nmode = drm_mode_create(dev);
 	if (!nmode)
 		return NULL;
 
-	new_id = nmode->base.id;
-	*nmode = *mode;
-	nmode->base.id = new_id;
-	INIT_LIST_HEAD(&nmode->head);
+	drm_mode_copy(nmode, mode);
+
 	return nmode;
 }
 EXPORT_SYMBOL(drm_mode_duplicate);

drivers/gpu/drm/nouveau/nv50_dac.c

@@ -190,11 +190,8 @@ nv50_dac_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
 	}
 
 	if (connector->scaling_mode != DRM_MODE_SCALE_NONE &&
-	     connector->native_mode) {
-		int id = adjusted_mode->base.id;
-		*adjusted_mode = *connector->native_mode;
-		adjusted_mode->base.id = id;
-	}
+	     connector->native_mode)
+		drm_mode_copy(adjusted_mode, connector->native_mode);
 
 	return true;
 }

drivers/gpu/drm/nouveau/nv50_sor.c

@@ -342,11 +342,8 @@ nv50_sor_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
 	}
 
 	if (connector->scaling_mode != DRM_MODE_SCALE_NONE &&
-	     connector->native_mode) {
-		int id = adjusted_mode->base.id;
-		*adjusted_mode = *connector->native_mode;
-		adjusted_mode->base.id = id;
-	}
+	     connector->native_mode)
+		drm_mode_copy(adjusted_mode, connector->native_mode);
 
 	return true;
 }

include/drm/drm_crtc.h

@@ -855,6 +855,7 @@ extern struct edid *drm_get_edid(struct drm_connector *connector,
 extern int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid);
 extern void drm_mode_probed_add(struct drm_connector *connector, struct drm_display_mode *mode);
 extern void drm_mode_remove(struct drm_connector *connector, struct drm_display_mode *mode);
+extern void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode *src);
 extern struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
 						   const struct drm_display_mode *mode);
 extern void drm_mode_debug_printmodeline(struct drm_display_mode *mode);