From patchwork Mon Jan 15 17:15:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thierry Escande X-Patchwork-Id: 10166159 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 5CFFA600CA for ; Tue, 16 Jan 2018 08:54:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3C55F251F4 for ; Tue, 16 Jan 2018 08:54:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 30C9827E63; Tue, 16 Jan 2018 08:54:17 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DE07D251F4 for ; Tue, 16 Jan 2018 08:54:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E75866E1B3; Tue, 16 Jan 2018 08:54:00 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2F5C26E14D for ; Mon, 15 Jan 2018 17:17:05 +0000 (UTC) Received: from localhost.localdomain (unknown [IPv6:2a01:e35:8a7e:4790:5118:57f7:752d:6fb0]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: tescande) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 72878270B64; Mon, 15 Jan 2018 17:17:03 +0000 (GMT) From: Thierry Escande To: Archit Taneja , Inki Dae , Thierry Reding , Sandy Huang , Sean Paul , David Airlie Subject: [PATCH 17/40] drm/bridge: analogix_dp: Wait for HPD signal before configuring link Date: Mon, 15 Jan 2018 18:15:51 +0100 Message-Id: <20180115171614.14474-18-thierry.escande@collabora.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20180115171614.14474-1-thierry.escande@collabora.com> References: <20180115171614.14474-1-thierry.escande@collabora.com> MIME-Version: 1.0 Content-Transfert-Encoding: 8bit X-Mailman-Approved-At: Tue, 16 Jan 2018 08:53:59 +0000 Cc: zain wang , Lin Huang , linux-kernel@vger.kernel.org, Douglas Anderson , dri-devel@lists.freedesktop.org, Tomasz Figa , linux-rockchip@lists.infradead.org, Yakir Yang , =?UTF-8?q?=C3=98rjan=20Eide?= , Mark Yao , Haixia Shi X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 --- 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 ba2506e17f6d..c940a5bb80ac 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1170,6 +1170,17 @@ 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;