From: jsg <jsg@openbsd.org>
Date: Thu, 4 Apr 2024 07:20:55 +0000 (+0000)
Subject: drm/probe-helper: warn about negative .get_modes()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=9801e47d4248d711f1b973c18b7ab8323ea414e3;p=openbsd

drm/probe-helper: warn about negative .get_modes()

From Jani Nikula
12bbe2c25cdb571190d523fd814e7696964a84d9 in linux-6.6.y/6.6.24
7af03e688792293ba33149fb8df619a8dff90e80 in mainline linux
---

diff --git a/sys/dev/pci/drm/drm_probe_helper.c b/sys/dev/pci/drm/drm_probe_helper.c
index e5ccdc8f29b..169df0488e6 100644
--- a/sys/dev/pci/drm/drm_probe_helper.c
+++ b/sys/dev/pci/drm/drm_probe_helper.c
@@ -419,6 +419,13 @@ static int drm_helper_probe_get_modes(struct drm_connector *connector)
 
 	count = connector_funcs->get_modes(connector);
 
+	/* The .get_modes() callback should not return negative values. */
+	if (count < 0) {
+		drm_err(connector->dev, ".get_modes() returned %pe\n",
+			ERR_PTR(count));
+		count = 0;
+	}
+
 	/*
 	 * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
 	 * override/firmware EDID.
diff --git a/sys/dev/pci/drm/include/drm/drm_modeset_helper_vtables.h b/sys/dev/pci/drm/include/drm/drm_modeset_helper_vtables.h
index e3c3ac61590..159213786e6 100644
--- a/sys/dev/pci/drm/include/drm/drm_modeset_helper_vtables.h
+++ b/sys/dev/pci/drm/include/drm/drm_modeset_helper_vtables.h
@@ -898,7 +898,8 @@ struct drm_connector_helper_funcs {
 	 *
 	 * RETURNS:
 	 *
-	 * The number of modes added by calling drm_mode_probed_add().
+	 * The number of modes added by calling drm_mode_probed_add(). Return 0
+	 * on failures (no modes) instead of negative error codes.
 	 */
 	int (*get_modes)(struct drm_connector *connector);