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: 10324129 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 B17236032A for ; Thu, 5 Apr 2018 09:57:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0C1F29145 for ; Thu, 5 Apr 2018 09:57:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 94B2629147; Thu, 5 Apr 2018 09:57:09 +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=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E380329146 for ; Thu, 5 Apr 2018 09:57:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4XNQSuzx4DFS/XZyVIt2KVNB9MyJY7Yv9UXupILaH+k=; b=lxPX9KXHuBEIdd WncEebo5ukLq7mbYdTpl34EjwagmT9+J1130kIxMnt76WGJo7btBdIXHfiri5/osIMf28UILFeBr1 c0db0R8RCpKgs/vwFLsynXNC6jxZs18MZEMSEQQN30nM+ATfV2vNee8KpZkI4RhP3qd+J4IjnFm2y tIMWNWUjtTUHPfFM8LdGtSFerF2MIFF/xeCr7YtPITcRfPy3HbPgD9aggqEn8OwFO0kES1L29Anzy KY6+ZYqf93K66lpLP8KpwfZd2710hbOTBuINJJfeiZubc5pOZNaEDVv7m3Dd5rRK2mVJVWeuW47/m uQ6nDkoI3Gydn3Ok51Xw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1f41dZ-0003S7-LF; Thu, 05 Apr 2018 09:56:57 +0000 Received: from bhuna.collabora.co.uk ([46.235.227.227]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1f41XS-0006xg-PM; Thu, 05 Apr 2018 09:50:44 +0000 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180405_025039_027783_AB094586 X-CRM114-Status: UNSURE ( 9.40 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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=20Marchesin?= , 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, Enric Balletbo i Serra , kuankuan.y@gmail.com, hshi@chromium.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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;