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 44F32C433EF for ; Thu, 19 May 2022 11:19:50 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 72375113E62; Thu, 19 May 2022 11:19:49 +0000 (UTC) Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4AEAB11A114 for ; Thu, 19 May 2022 11:19:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652959187; x=1684495187; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:content-transfer-encoding:in-reply-to; bh=HZm2qOa9o29jmQRrlpayvPTgsHGqp2/VhEemJhv2WgA=; b=OF4wnrrvD3gpofns99ihdAlhPYnfPhZJOPkwHhUR8p2TbqN0tLwcPSzb JqVnFvvDHQIYi9rvTXlDYAi/qX6bK9rThso72UrYKb1H2bUQINruCEk9a Xy7JNeejUy/pMchPUmhblIVnqxPhldMaxBAi0MAx6TJ1qRqXQ1ZIGA2BS ssIThyEVJeRJEJnvANYefX4RIol0h2p5+zriJirzT4LwtiisH/Kp8vzw0 Vz8UxYTDWECSzpB+tnXtYqmljiKWN6L37vw/EL1XKj8A+litnuq5uJcQD 1OEkkge4RA/1MPx7xPQLVlMnT6EqJcYYgNVaW+l5AMvf8+y5PAgpAdvQO Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10351"; a="252670298" X-IronPort-AV: E=Sophos;i="5.91,237,1647327600"; d="scan'208";a="252670298" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2022 04:19:46 -0700 X-IronPort-AV: E=Sophos;i="5.91,237,1647327600"; d="scan'208";a="598507192" Received: from ideak-desk.fi.intel.com ([10.237.72.175]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2022 04:19:45 -0700 Date: Thu, 19 May 2022 14:19:41 +0300 From: Imre Deak To: "Kasireddy, Vivek" Message-ID: References: <20220516085402.3591249-1-vivek.kasireddy@intel.com> <20220516085402.3591249-3-vivek.kasireddy@intel.com> <6117cb32773745e980bc02bfab96bb21@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6117cb32773745e980bc02bfab96bb21@intel.com> Subject: Re: [Intel-gfx] [PATCH v1 2/2] drm/i915: Reject the atomic modeset if an associated Type-C port is disconnected 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: , Reply-To: imre.deak@intel.com Cc: "intel-gfx@lists.freedesktop.org" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, May 18, 2022 at 10:04:14AM +0300, Kasireddy, Vivek wrote: > Hi Imre, > > > On Mon, May 16, 2022 at 01:54:02AM -0700, Vivek Kasireddy wrote: > > > Although, doing a modeset on any disconnected connector might be futile, > > > it can be particularly problematic if the connector is a Type-C port > > > without a sink. And, the spec only says "Display software must not use > > > a disconnected port" while referring to the Type-C DDI seqeuence, it does > > > not spell out what happens if such an attempt is made. Experimental results > > > have shown that this can lead to serious issues including a system hang. > > > Therefore, reject the atomic modeset if we detect that the Type-C port > > > is not connected. > > > > > > Cc: Ville Syrjälä > > > Signed-off-by: Vivek Kasireddy > > > --- > > > drivers/gpu/drm/i915/display/intel_atomic.c | 20 ++++++++++++++++++++ > > > 1 file changed, 20 insertions(+) > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c > > b/drivers/gpu/drm/i915/display/intel_atomic.c > > > index 40da7910f845..40576964b8c1 100644 > > > --- a/drivers/gpu/drm/i915/display/intel_atomic.c > > > +++ b/drivers/gpu/drm/i915/display/intel_atomic.c > > > @@ -114,6 +114,8 @@ int intel_digital_connector_atomic_set_property(struct > > drm_connector *connector, > > > int intel_digital_connector_atomic_check(struct drm_connector *conn, > > > struct drm_atomic_state *state) > > > { > > > + struct drm_device *dev = conn->dev; > > > + struct drm_i915_private *dev_priv = to_i915(dev); > > > struct drm_connector_state *new_state = > > > drm_atomic_get_new_connector_state(state, conn); > > > struct intel_digital_connector_state *new_conn_state = > > > @@ -122,6 +124,10 @@ int intel_digital_connector_atomic_check(struct > > drm_connector *conn, > > > drm_atomic_get_old_connector_state(state, conn); > > > struct intel_digital_connector_state *old_conn_state = > > > to_intel_digital_connector_state(old_state); > > > + struct intel_encoder *encoder = > > > + intel_attached_encoder(to_intel_connector(conn)); > > > + struct intel_digital_port *dig_port = > > > + encoder ? enc_to_dig_port(encoder) : NULL; > > > struct drm_crtc_state *crtc_state; > > > > > > intel_hdcp_atomic_check(conn, old_state, new_state); > > > @@ -131,6 +137,20 @@ int intel_digital_connector_atomic_check(struct drm_connector *conn, > > > > > > crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc); > > > > > > + /* > > > + * The spec says that it is not safe to use a disconnected Type-C port. > > > + * Therefore, check to see if this connector is connected and reject > > > + * the modeset if there is no sink detected. > > > + */ > > > + if (dig_port && !dig_port->connected(encoder) && > > > > This check is racy, as right after dig_port->connected() returns true, > > the port can become disconnected. > > [Kasireddy, Vivek] Given that, do you think the only way to reliably determine > if the Type-C port has a sink is to check the live status and ignore dig_port->tc_mode? > > If that is the case, should I just add a function pointer to dig_port to call > tc_port_live_status_mask()? Or, should I just change intel_tc_port_connected() > to ignore dig_port->tc_mode like below: > @@ -764,8 +764,7 @@ bool intel_tc_port_connected(struct intel_encoder *encoder) > > intel_tc_port_lock(dig_port); > > - is_connected = tc_port_live_status_mask(dig_port) & > - BIT(dig_port->tc_mode); > + is_connected = tc_port_live_status_mask(dig_port); > > Or, are there any other elegant ways that you can think of to determine whether > a tc port has a sink or not? I meant that I don't think there is a way to prevent a modeset on a disconnected port. Live status is what provides the connected state, but it can change right after it is read out. > Thanks, > Vivek > > > > > > + intel_phy_is_tc(dev_priv, > > > + intel_port_to_phy(dev_priv, encoder->port))) { > > > + drm_dbg_atomic(&dev_priv->drm, > > > + "[CONNECTOR:%d:%s] is not connected; rejecting the > > modeset\n", > > > + conn->base.id, conn->name); > > > + return -EINVAL; > > > + } > > > + > > > /* > > > * These properties are handled by fastset, and might not end > > > * up in a modeset. > > > -- > > > 2.35.1 > > >