drm/probe-helper: Add helper for drm_helper_probe_single_connector_modes()

The drm_helper_probe_single_connector_modes() is a bit long. Let's
break a chunk off to update and validate modes. This helps avoid one
goto and also will allow us to more easily call the helper a second
time in a future patch without adding looping or another goto.

This change is intended to be a no-op change--just code movement.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220511155749.v3.1.I2dd93486c6952bd52f2020904de0133970d11b29@changeid

drivers/gpu/drm/drm_probe_helper.c

@@ -354,6 +354,61 @@ drm_helper_probe_detect(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_helper_probe_detect);
 
+static int __drm_helper_update_and_validate(struct drm_connector *connector,
+					    uint32_t maxX, uint32_t maxY,
+					    struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_display_mode *mode;
+	int mode_flags = 0;
+	int ret;
+
+	drm_connector_list_update(connector);
+
+	if (connector->interlace_allowed)
+		mode_flags |= DRM_MODE_FLAG_INTERLACE;
+	if (connector->doublescan_allowed)
+		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
+	if (connector->stereo_allowed)
+		mode_flags |= DRM_MODE_FLAG_3D_MASK;
+
+	list_for_each_entry(mode, &connector->modes, head) {
+		if (mode->status != MODE_OK)
+			continue;
+
+		mode->status = drm_mode_validate_driver(dev, mode);
+		if (mode->status != MODE_OK)
+			continue;
+
+		mode->status = drm_mode_validate_size(mode, maxX, maxY);
+		if (mode->status != MODE_OK)
+			continue;
+
+		mode->status = drm_mode_validate_flag(mode, mode_flags);
+		if (mode->status != MODE_OK)
+			continue;
+
+		ret = drm_mode_validate_pipeline(mode, connector, ctx,
+						 &mode->status);
+		if (ret) {
+			drm_dbg_kms(dev,
+				    "drm_mode_validate_pipeline failed: %d\n",
+				    ret);
+
+			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK))
+				mode->status = MODE_ERROR;
+			else
+				return -EDEADLK;
+		}
+
+		if (mode->status != MODE_OK)
+			continue;
+		mode->status = drm_mode_validate_ycbcr420(mode, connector);
+	}
+
+	return 0;
+}
+
 /**
  * drm_helper_probe_single_connector_modes - get complete set of display modes
  * @connector: connector to probe
@@ -421,7 +476,6 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 	const struct drm_connector_helper_funcs *connector_funcs =
 		connector->helper_private;
 	int count = 0, ret;
-	int mode_flags = 0;
 	bool verbose_prune = true;
 	enum drm_connector_status old_status;
 	struct drm_modeset_acquire_ctx ctx;
@@ -519,54 +573,14 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 			   connector->status == connector_status_unknown))
 		count = drm_add_modes_noedid(connector, 1024, 768);
 	count += drm_helper_probe_add_cmdline_mode(connector);
-	if (count == 0)
-		goto prune;
-
-	drm_connector_list_update(connector);
-
-	if (connector->interlace_allowed)
-		mode_flags |= DRM_MODE_FLAG_INTERLACE;
-	if (connector->doublescan_allowed)
-		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
-	if (connector->stereo_allowed)
-		mode_flags |= DRM_MODE_FLAG_3D_MASK;
-
-	list_for_each_entry(mode, &connector->modes, head) {
-		if (mode->status != MODE_OK)
-			continue;
-
-		mode->status = drm_mode_validate_driver(dev, mode);
-		if (mode->status != MODE_OK)
-			continue;
-
-		mode->status = drm_mode_validate_size(mode, maxX, maxY);
-		if (mode->status != MODE_OK)
-			continue;
-
-		mode->status = drm_mode_validate_flag(mode, mode_flags);
-		if (mode->status != MODE_OK)
-			continue;
-
-		ret = drm_mode_validate_pipeline(mode, connector, &ctx,
-						 &mode->status);
-		if (ret) {
-			drm_dbg_kms(dev,
-				    "drm_mode_validate_pipeline failed: %d\n",
-				    ret);
-
-			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK)) {
-				mode->status = MODE_ERROR;
-			} else {
+	if (count != 0) {
+		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
+		if (ret == -EDEADLK) {
 			drm_modeset_backoff(&ctx);
 			goto retry;
 		}
 	}
 
-		if (mode->status != MODE_OK)
-			continue;
-		mode->status = drm_mode_validate_ycbcr420(mode, connector);
-	}
-
 prune:
 	drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);