From bf1e1a796198e8e220a0bd1cd6a5f346f4f9b3fa Mon Sep 17 00:00:00 2001
From: llyyr <llyyr.public@gmail.com>
Date: Mon, 14 Aug 2023 19:14:16 +0530
Subject: drm_common: skip cards that don't have connected outputs

It's possible for systems to have multiple cards, and the first capable
card to not have a connected output. Skip such cards and continue
iterating until we find one with a connected output.
---
 video/out/drm_common.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'video')

diff --git a/video/out/drm_common.c b/video/out/drm_common.c
index b4064879de..0ec0788480 100644
--- a/video/out/drm_common.c
+++ b/video/out/drm_common.c
@@ -816,6 +816,24 @@ static bool card_supports_kms(const char *path)
     return ret;
 }
 
+static bool card_has_connection(const char *path)
+{
+    int fd = open_card_path(path);
+    bool ret = false;
+    if (fd != -1) {
+        drmModeRes *res = drmModeGetResources(fd);
+        if (res) {
+            drmModeConnector *connector = get_first_connected_connector(res, fd);
+            if (connector)
+                ret = true;
+            drmModeFreeConnector(connector);
+            drmModeFreeResources(res);
+        }
+        close(fd);
+    }
+    return ret;
+}
+
 static void get_primary_device_path(struct vo_drm_state *drm)
 {
     if (drm->opts->device_path) {
@@ -865,6 +883,17 @@ static void get_primary_device_path(struct vo_drm_state *drm)
             continue;
         }
 
+        if (!card_has_connection(card_path)) {
+            if (card_no_given) {
+                MP_ERR(drm,
+                        "DRM card number %d given, but it does not have any "
+                        "connected outputs.\n", i);
+                break;
+            }
+
+            continue;
+        }
+
         MP_VERBOSE(drm, "Picked DRM card %d, primary node %s%s.\n",
                    i, card_path,
                    card_no_given ? "" : " as the default");
-- 
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