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 5265CC433F5 for ; Mon, 16 May 2022 09:54:19 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6DF9E10E361; Mon, 16 May 2022 09:54:18 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id B465110E2E3 for ; Mon, 16 May 2022 09:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652694856; x=1684230856; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:content-transfer-encoding:in-reply-to; bh=yKvriAhEXp/K9ejkLHN7Dn7pTBbToY+CIyyV4RxKtq8=; b=l4xsMy+tvZRhEe9nNax1hs1zUIPCr2oVDHgTH3eboxjGWQgtgEEnaUVt 42Owq/WfgLsh2e96eth7dkQ2FAiV52lMs/z1tyUZPFpDqz6AvqdvF5AOJ pxYnwKU2a5qsnuNDnYjBMSYk+ZvR+YujADYYsJ7uL3/PbS3KDRzSWTmG6 jfOhkh4pVoETH6M6PyZalMOGBLj7s1MWcpvyRzEdnnhriTvSzeTEvqMy1 DPTzW6v2pyDhgKKQmNWn0iHGUBNJpO4Pgz39o0Bzcf8rIH2fP7y5n+1Yk f7pFiXXw/anEPK0dfzNZEf3tvAvy4LKImqy8IZFeC0Bqfej5RX9irlajy g==; X-IronPort-AV: E=McAfee;i="6400,9594,10348"; a="250679044" X-IronPort-AV: E=Sophos;i="5.91,229,1647327600"; d="scan'208";a="250679044" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 May 2022 02:54:16 -0700 X-IronPort-AV: E=Sophos;i="5.91,229,1647327600"; d="scan'208";a="699460049" Received: from ideak-desk.fi.intel.com ([10.237.72.175]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 May 2022 02:54:13 -0700 Date: Mon, 16 May 2022 12:54:09 +0300 From: Imre Deak To: Vivek Kasireddy Message-ID: References: <20220516085402.3591249-1-vivek.kasireddy@intel.com> <20220516085402.3591249-3-vivek.kasireddy@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220516085402.3591249-3-vivek.kasireddy@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 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. > + 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 >