From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB634C43334 for ; Wed, 8 Jun 2022 10:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236437AbiFHKfG (ORCPT ); Wed, 8 Jun 2022 06:35:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237925AbiFHKdW (ORCPT ); Wed, 8 Jun 2022 06:33:22 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60FB9296317; Wed, 8 Jun 2022 03:27:06 -0700 (PDT) X-UUID: 7ce3e81b0211425a9202e780efe66aeb-20220608 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.5,REQID:715d832e-f55f-4544-b15e-841338791c1f,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-META: VersionHash:2a19b09,CLOUDID:62c219e5-2ba2-4dc1-b6c5-11feb6c769e0,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:0,BEC:nil X-UUID: 7ce3e81b0211425a9202e780efe66aeb-20220608 Received: from mtkexhb02.mediatek.inc [(172.21.101.103)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 510881272; Wed, 08 Jun 2022 18:26:34 +0800 Received: from mtkmbs11n1.mediatek.inc (172.21.101.186) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.15; Wed, 8 Jun 2022 18:26:34 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Wed, 8 Jun 2022 18:26:33 +0800 Message-ID: <75c00caca74b8366ca2c4594a8229b6de95c5f47.camel@mediatek.com> Subject: Re: [PATCH v10 18/21] drm/mediatek: Add mt8195 Embedded DisplayPort driver From: Rex-BC Chen To: CK Hu , Guillaume Ranquet , Chun-Kuang Hu , Philipp Zabel , David Airlie , Daniel Vetter , Rob Herring , Krzysztof Kozlowski , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Matthias Brugger , Chunfeng Yun =?UTF-8?Q?=28=E4=BA=91=E6=98=A5=E5=B3=B0=29?= , Kishon Vijay Abraham I , Vinod Koul , "Helge Deller" , Jitao Shi =?UTF-8?Q?=28=E7=9F=B3=E8=AE=B0=E6=B6=9B=29?= CC: Markus Schneider-Pargmann , "dri-devel@lists.freedesktop.org" , "linux-mediatek@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-phy@lists.infradead.org" , "linux-fbdev@vger.kernel.org" Date: Wed, 8 Jun 2022 18:26:33 +0800 In-Reply-To: References: <20220523104758.29531-1-granquet@baylibre.com> <20220523104758.29531-19-granquet@baylibre.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, 2022-06-07 at 15:47 +0800, CK Hu wrote: > Hi, Rex: > > On Mon, 2022-05-23 at 12:47 +0200, Guillaume Ranquet wrote: > > From: Markus Schneider-Pargmann > > > > This patch adds a DisplayPort driver for the Mediatek mt8195 SoC. > > > > It supports the mt8195, the embedded DisplayPort units. It offers > > DisplayPort 1.4 with up to 4 lanes. > > > > The driver creates a child device for the phy. The child device > > will > > never exist without the parent being active. As they are sharing a > > register range, the parent passes a regmap pointer to the child so > > that > > both can work with the same register range. The phy driver sets > > device > > data that is read by the parent to get the phy device that can be > > used > > to control the phy properties. > > > > This driver is based on an initial version by > > Jason-JH.Lin . > > > > Signed-off-by: Markus Schneider-Pargmann > > Signed-off-by: Guillaume Ranquet > > --- > > [snip] > > > + > > +static int mtk_dp_hpd_sink_event(struct mtk_dp *mtk_dp) > > +{ > > + ssize_t ret; > > + u8 sink_count; > > + bool locked; > > + u8 link_status[DP_LINK_STATUS_SIZE] = {}; > > + u32 sink_count_reg = DP_SINK_COUNT_ESI; > > + u32 link_status_reg = DP_LANE0_1_STATUS; > > + > > + ret = drm_dp_dpcd_readb(&mtk_dp->aux, sink_count_reg, > > &sink_count); > > + if (ret < 0) { > > + drm_err(mtk_dp->drm_dev, "Read sink count failed: > > %ld\n", ret); > > + return ret; > > + } > > + > > + ret = drm_dp_dpcd_read(&mtk_dp->aux, link_status_reg, > > link_status, > > + sizeof(link_status)); > > + if (!ret) { > > + drm_err(mtk_dp->drm_dev, "Read link status failed: > > %ld\n", > > + ret); > > + return ret; > > + } > > + > > + locked = drm_dp_channel_eq_ok(link_status, > > + mtk_dp->train_info.lane_count); > > + if (!locked && mtk_dp->train_state > > > MTK_DP_TRAIN_STATE_TRAINING_PRE) > > Before enter this function, mtk_dp->train_state is set to > MTK_DP_TRAIN_STATE_STARTUP, so this never happen, drop this. > The interrupt from sink device could come any time. Why it's impossible? > > + mtk_dp->train_state = MTK_DP_TRAIN_STATE_TRAINING_PRE; > > + > > + if (link_status[1] & DP_REMOTE_CONTROL_COMMAND_PENDING) > > + drm_dp_dpcd_writeb(&mtk_dp->aux, > > DP_DEVICE_SERVICE_IRQ_VECTOR, > > + DP_REMOTE_CONTROL_COMMAND_PENDING); > > + > > + if (DP_GET_SINK_COUNT(sink_count) && > > + (link_status[2] & DP_DOWNSTREAM_PORT_STATUS_CHANGED)) { > > + mtk_dp->train_info.check_cap_count = 0; > > + mtk_dp->train_state = MTK_DP_TRAIN_STATE_CHECKEDID; > > Why change state from MTK_DP_TRAIN_STATE_STARTUP to > MTK_DP_TRAIN_STATE_CHECKEDID? In mtk_dp_train_handler(), > mtk_dp_parse_capabilities() is true then change to > MTK_DP_TRAIN_STATE_CHECKEDID. Give a reason why these two are > different. > > Regards, > CK > I will drop this and drop state of MTK_DP_TRAIN_STATE_CHECKEDID. MTK_DP_TRAIN_STATE_CHECKEDID is only used for audio. We can check enable status in another place. BRs, Bo-Chen > > + msleep(20); > > + } > > + > > + return 0; > > +} > > + > >