From 35f881ca59d6f8bbf49889a792d3539d9bab6ed2 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Mon, 9 Oct 2023 16:34:36 +0100
Subject: [PATCH 0679/1085] drm/fb-helper: Look up preferred fbdev node number
 from DT

For situations where there are multiple DRM cards in a system,
add a query of DT for "drm_fb" designations for cards to set
their preferred /dev/fbN designation.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1840,7 +1840,7 @@ __drm_fb_helper_initial_config_and_unloc
 	struct drm_device *dev = fb_helper->dev;
 	struct fb_info *info;
 	unsigned int width, height;
-	int ret;
+	int ret, id;
 
 	width = dev->mode_config.max_width;
 	height = dev->mode_config.max_height;
@@ -1868,6 +1868,15 @@ __drm_fb_helper_initial_config_and_unloc
 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
 	mutex_unlock(&fb_helper->lock);
 
+	id = of_alias_get_highest_id("drm_fb");
+	if (id >= 0)
+		fb_set_lowest_dynamic_fb(id + 1);
+
+	id = of_alias_get_id(dev->dev->of_node, "drm_fb");
+	if (id >= 0) {
+		info->node = id;
+		info->custom_fb_num = true;
+	}
 	ret = register_framebuffer(info);
 	if (ret < 0)
 		return ret;
