From patchwork Thu Nov 28 03:08:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liankun Yang X-Patchwork-Id: 13887666 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 83247D6D258 for ; Thu, 28 Nov 2024 03:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=AOBziDuT5YTUhpLHkhqSfJSif72YhhrKJJn81tVZRIs=; b=tKF6dzPACp9it7+3R035Ahh4eP dGQsHtJJa056BwAe2GvJ7sBDCNsobmdOcJ6GF6Ogjv/SGLbOu03dszQ/twBF7FY6XSvj4aJkQt65s hc6iCqqkdbFj55dodcww2oLrC0Ze6xE6xe/zZBPdTXPb5VRY0cdUrE6uZzDxrpXx1mamfXb+a500b 1Ecicp8lrh6X/Xf3eBzp866wCR29OHl6hM9fUuHOpjhbgzbSwmdQpvYIXYCWJIhQMgSpY2OPYtPzx liURwnJyjf00UGqLY0Hd7T+306rLf1f5dvqgMKXPjF6Ur3wBrpx0q3m+rzIuZsny2e4yUzcmRhtrL cacL3EQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tGUvb-0000000Eak8-1Sa2; Thu, 28 Nov 2024 03:10:51 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tGUub-0000000EaYu-09Xb; Thu, 28 Nov 2024 03:09:50 +0000 X-UUID: 387a88f4ad3611ef9048ed6ed365623b-20241127 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=AOBziDuT5YTUhpLHkhqSfJSif72YhhrKJJn81tVZRIs=; b=pIcHdo6LwbbOQcYdfdw4V+y4Pe3znAEA+7+mnTN+2mOjrP2i6MgG6LpMTTp7SU9Fa9Iwlj9yrKVxJdnMDm8Tjw+j3S+IwKEJmE5PrtoKY1LtGVjC9ms6HdRqz/wc7iKNjmKXOxeEzpuWBq797WxA20i64jkMuIhg4wIfHtY86SM=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.44,REQID:9f1e6710-7a5d-4032-bbe6-49e6ec61dda0,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:464815b,CLOUDID:29099f23-634f-4016-85ba-2d63e55c9400,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:1,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1, SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 0,NGT X-CID-BAS: 0,NGT,0,_ X-CID-FACTOR: TF_CID_SPAM_ULS,TF_CID_SPAM_SNR X-UUID: 387a88f4ad3611ef9048ed6ed365623b-20241127 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 452076117; Wed, 27 Nov 2024 20:09:45 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by mtkmbs13n1.mediatek.inc (172.21.101.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Thu, 28 Nov 2024 11:09:42 +0800 Received: from mszsdclx1211.gcn.mediatek.inc (10.16.7.31) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Thu, 28 Nov 2024 11:09:42 +0800 From: Liankun Yang To: , , , , , , , , , , , , , , CC: , , , Subject: [PATCH v2 1/1] drm/mediatek: Add return value check when reading DPCD Date: Thu, 28 Nov 2024 11:08:16 +0800 Message-ID: <20241128030940.25657-1-liankun.yang@mediatek.com> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241127_190949_075651_8D70F23D X-CRM114-Status: GOOD ( 13.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Returns the number of bytes transferred (1) on success. Check the return value to confirm that AUX communication is successful. Fixes: d9e6ea02fc3f ("drm/mediatek: dp: Add MT8195 External DisplayPort support") Signed-off-by: Liankun Yang --- Changes in V2: - Modify Fixes in Commit Message. Per suggestion from the previous thread: https://patchwork.kernel.org/project/linux-mediatek/patch/20240930092000.5385-1-liankun.yang@mediatek.com/ --- drivers/gpu/drm/mediatek/mtk_dp.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 1cc916b16471..9dc68ec2ff43 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -2101,6 +2101,7 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge) enum drm_connector_status ret = connector_status_disconnected; bool enabled = mtk_dp->enabled; u8 sink_count = 0; + size_t value; if (!mtk_dp->train_info.cable_plugged_in) return ret; @@ -2115,7 +2116,12 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge) * function, we just need to check the HPD connection to check * whether we connect to a sink device. */ - drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT, &sink_count); + value = drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT, &sink_count); + if (value < 0) { + drm_err(mtk_dp->drm_dev, "Failed to read DP Sink Count: %zd\n", value); + return ret; + } + if (DP_GET_SINK_COUNT(sink_count)) ret = connector_status_connected;