From: jsg <jsg@openbsd.org>
Date: Thu, 24 Feb 2022 12:59:55 +0000 (+0000)
Subject: drm/i915/opregion: check port number bounds for SWSCI display power state
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2e7e0e6549dab5fd057677d09ccf0c05a92a4bf9;p=openbsd

drm/i915/opregion: check port number bounds for SWSCI display power state

From Jani Nikula
d006f2fe7d627b3ff3f637cf2fa90d30e05887c9 in linux 5.15.y/5.15.25
ea958422291de248b9e2eaaeea36004e84b64043 in mainline linux
---

diff --git a/sys/dev/pci/drm/i915/display/intel_opregion.c b/sys/dev/pci/drm/i915/display/intel_opregion.c
index abbe6e852bd..df469af1667 100644
--- a/sys/dev/pci/drm/i915/display/intel_opregion.c
+++ b/sys/dev/pci/drm/i915/display/intel_opregion.c
@@ -361,6 +361,21 @@ int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
 		port++;
 	}
 
+	/*
+	 * The port numbering and mapping here is bizarre. The now-obsolete
+	 * swsci spec supports ports numbered [0..4]. Port E is handled as a
+	 * special case, but port F and beyond are not. The functionality is
+	 * supposed to be obsolete for new platforms. Just bail out if the port
+	 * number is out of bounds after mapping.
+	 */
+	if (port > 4) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "[ENCODER:%d:%s] port %c (index %u) out of bounds for display power state notification\n",
+			    intel_encoder->base.base.id, intel_encoder->base.name,
+			    port_name(intel_encoder->port), port);
+		return -EINVAL;
+	}
+
 	if (!enable)
 		parm |= 4 << 8;