From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6BAF7CA5FC4 for ; Fri, 2 Oct 2026 09:21:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DA8D510E424; Fri, 2 Oct 2026 09:21:24 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="mD27VtXp"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1058310E424; Fri, 2 Oct 2026 09:21:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1790932884; x=1822468884; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=4vYXbS5N0wrk0QB36Cvdfxop/53SZQBVGCH1DIOvIV0=; b=mD27VtXp9ZuCf59ZL3yNEBaKju9uGAMqSkBdo+UdR1cgikMDRl39QXq3 o4sWeB4m0UJqV//7WMX+LwwlqChz9FqdDoPN9eB9j7ydgmgnqNidc42r2 6xdcvgwz0WlMpm5JpCdWDURR4Ark9iIo63axVgHn7+G5Jr5BdZza9MO/Q m9I4A/gyPtaxSU9vDBjbXsalagsiLZyYdweL62Yjgpw8IZHBHPMcUwJKK B6LXsKuwPSUaH6wzu1Bbkto5TWANxesEkXUyWc2H9OwzSvlpsofgr10ib DUzLuEOzMyy1vQ9f0OBGyitBzfZIzGKKIONnv4genK6zIvmBiyF8hEFoc w==; X-CSE-ConnectionGUID: 9/5AO1pvRg6e3/cZvsKh9w== X-CSE-MsgGUID: CZCcF5dVT7S5hOTUI0uvag== X-IronPort-AV: E=McAfee;i="6800,10657,11922"; a="90728933" X-IronPort-AV: E=Sophos;i="6.27,136,1787036400"; d="scan'208";a="90728933" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2026 02:21:23 -0700 X-CSE-ConnectionGUID: uhzSw154Siec8f0GPq9KxA== X-CSE-MsgGUID: RSCYN8imRSWQtN6/P8aR/g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,136,1787036400"; d="scan'208";a="302464397" Received: from slindbla-desk.ger.corp.intel.com (HELO localhost) ([10.245.244.196]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2026 02:21:21 -0700 From: Jani Nikula To: FNU VISHWANATHA , dri-devel@lists.freedesktop.org Cc: intel-gfx@lists.freedesktop.org, FNU VISHWANATHA Subject: Re: [PATCH 1/2] drm/mst: Fix sporadic second display not detected after warm boot/G3 In-Reply-To: <20261001215705.3891147-1-fnu.vishwanatha@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland References: <20261001215705.3891147-1-fnu.vishwanatha@intel.com> Date: Fri, 02 Oct 2026 12:21:19 +0300 Message-ID: <3ddffda7b123f83a4dc94d26f299dec08da27fba@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, 01 Oct 2026, FNU VISHWANATHA wrote: > The intermittent detection failure of the second display over MST HUB is caused > by a race condition in MST port status detection during warm boot/G3 resume. > > When a port transitions from input to output state during topology reprobe, the > driver was not forcing a re-probe of the link address. This caused ports that > were temporarily incorrectly marked as input ports to never create connectors. > > Force a link address reprobe when a port transitions from input (1) to output > (0) state, giving the MST hub another chance to properly report the port status. > > Signed-off-by: FNU VISHWANATHA Is there a bug report about this with logs? > --- > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c > index be749dcad3b5..cc340e4235cc 100644 > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c > @@ -2377,7 +2377,11 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, > changed = true; > created = true; > } else if (port->input && !port_msg->input_port) { > + /* Port transitioned from input to output (e.g., during warm boot/G3 resume) > + * We need to force link address reprobe to get proper port info > + */ > changed = true; > + mstb->link_address_sent = false; > } else if (port->connector) { > /* We're updating a port that's exposed to userspace, so do it > * under lock -- Jani Nikula, Intel