From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59392 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728480AbeIXSpE (ORCPT ); Mon, 24 Sep 2018 14:45:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Yang , Charlene Liu , Harry Wentland , Alex Deucher , Sasha Levin Subject: [PATCH 4.18 195/235] drm/amd/display: support access ddc for mst branch Date: Mon, 24 Sep 2018 13:53:01 +0200 Message-Id: <20180924113123.810864196@linuxfoundation.org> In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Yang [ Upstream commit 0a14544661fad1606cc96aece30b2950fd9c4c81 ] [Why] Megachip dockings accesses ddc line through display driver when installing FW. Previously, we would fail every transaction because link attached to mst branch did not have their ddc transaction type set. [How] Set ddc transaction type when mst branch is connected. Signed-off-by: Eric Yang Reviewed-by: Charlene Liu Acked-by: Harry Wentland Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -497,6 +497,10 @@ static bool detect_dp( sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT_MST; link->type = dc_connection_mst_branch; + dal_ddc_service_set_transaction_type( + link->ddc, + sink_caps->transaction_type); + /* * This call will initiate MST topology discovery. Which * will detect MST ports and add new DRM connector DRM