From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753402AbeCNGJr (ORCPT ); Wed, 14 Mar 2018 02:09:47 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:33964 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbeCNGJo (ORCPT ); Wed, 14 Mar 2018 02:09:44 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org BEE0A60B67 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=architt@codeaurora.org Subject: Re: [PATCH v5 11/36] drm/bridge: analogix_dp: Wait for HPD signal before configuring link To: Enric Balletbo i Serra , 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, linux-kernel@vger.kernel.org, a.hajda@samsung.com, Laurent.pinchart@ideasonboard.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, =?UTF-8?Q?St=c3=a9phane_Marchesin?= , 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, dianders@chromium.org, kyungmin.park@samsung.com, kuankuan.y@gmail.com, hshi@chromium.org References: <20180309222327.18689-1-enric.balletbo@collabora.com> <20180309222327.18689-12-enric.balletbo@collabora.com> From: Archit Taneja Message-ID: <636d85d6-64bb-5387-912d-1ec09e47f0ef@codeaurora.org> Date: Wed, 14 Mar 2018 11:39:27 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180309222327.18689-12-enric.balletbo@collabora.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 10 March 2018 03:53 AM, Enric Balletbo i Serra wrote: > 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. Reviewed-by: Archit Taneja Thanks, Archit > > 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 > --- > > 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 c81733b8185e..92fb9a072cb6 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; >