From patchwork Thu Apr 5 09:49:35 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Enric Balletbo i Serra X-Patchwork-Id: 10324263 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7EC06600CB for ; Thu, 5 Apr 2018 10:02:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6D885290D7 for ; Thu, 5 Apr 2018 10:02:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 61965290DD; Thu, 5 Apr 2018 10:02:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 09B40290D7 for ; Thu, 5 Apr 2018 10:02:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751759AbeDEKC2 (ORCPT ); Thu, 5 Apr 2018 06:02:28 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:60566 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbeDEJuY (ORCPT ); Thu, 5 Apr 2018 05:50:24 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id F2C6D27A64E From: Enric Balletbo i Serra To: architt@codeaurora.org, inki.dae@samsung.com, thierry.reding@gmail.com, hjc@rock-chips.com, seanpaul@chromium.org, airlied@linux.ie, tfiga@chromium.org, heiko@sntech.de Cc: dri-devel@lists.freedesktop.org, dianders@chromium.org, a.hajda@samsung.com, ykk@rock-chips.com, kernel@collabora.com, m.szyprowski@samsung.com, linux-samsung-soc@vger.kernel.org, jy0922.shim@samsung.com, rydberg@bitmath.org, krzk@kernel.org, linux-rockchip@lists.infradead.org, kgene@kernel.org, linux-input@vger.kernel.org, orjan.eide@arm.com, wxt@rock-chips.com, jeffy.chen@rock-chips.com, linux-arm-kernel@lists.infradead.org, mark.yao@rock-chips.com, wzz@rock-chips.com, hl@rock-chips.com, jingoohan1@gmail.com, sw0312.kim@samsung.com, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, Laurent.pinchart@ideasonboard.com, kuankuan.y@gmail.com, hshi@chromium.org, =?UTF-8?q?St=C3=A9phane=20Marchesin?= , Enric Balletbo i Serra Subject: [PATCH v6 05/30] drm/bridge: analogix_dp: Wait for HPD signal before configuring link Date: Thu, 5 Apr 2018 11:49:35 +0200 Message-Id: <20180405095000.9756-6-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180405095000.9756-1-enric.balletbo@collabora.com> References: <20180405095000.9756-1-enric.balletbo@collabora.com> MIME-Version: 1.0 Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: zain wang According to DP spec v1.3 chap 3.5.1.2 Link Training, Link Policy Maker must first detect that the HPD signal is asserted high by the Downstream Device before establishing a link with it. Cc: Stéphane Marchesin Signed-off-by: zain wang Signed-off-by: Sean Paul Signed-off-by: Thierry Escande Signed-off-by: Enric Balletbo i Serra Tested-by: Marek Szyprowski Reviewed-by: Archit Taneja --- drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index bf805f156272..3269deec739d 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1169,6 +1169,17 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp) if (ret) goto out_dp_init; + /* + * According to DP spec v1.3 chap 3.5.1.2 Link Training, + * We should first make sure the HPD signal is asserted high by device + * when we want to establish a link with it. + */ + ret = analogix_dp_detect_hpd(dp); + if (ret) { + DRM_ERROR("failed to get hpd single ret = %d\n", ret); + goto out_dp_init; + } + ret = analogix_dp_commit(dp); if (ret) goto out_dp_init;