From patchwork Mon Sep 30 09:17:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liankun Yang X-Patchwork-Id: 13815731 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 EAEEDCF649D for ; Mon, 30 Sep 2024 09:27:33 +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=yqgHKnptu5bK43gGLrnEqqpfwTrlY1ULN7Za2e2rfGM=; b=JJt/ctV65aX+OGuk2D5bhVsXAT wqgXVymOTVCuxLIZb5J9nDE5+qkYuGIP+zZAkCk845W481G8xvXc8kvtxr7rQPbAvdo3iwgekZivg evQ0JeRBnZrOUjKKkCZAqpSsCdkX4BZWQ7tUf4bXXPNiBAObHl/RD3tka9mBuPUfeInfbLHdLLMBf kbIKREo9LqZpXPvOU/Fg0w0L3v1FBBH8sJe+9TdXvleIHlnKalX9ZmMOSN1roNvaIAnjWyOVdjl/4 X1OPWb3HZrBCMHWcW8XaW+GSVWMdt9K+1Rsdlfdh9VMNEM7ez1PtxXt1cf+Wv0RBUJ6Ht6/kdmPXj mkDVhJ0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1svCgd-0000000GW8R-3Fv3; Mon, 30 Sep 2024 09:27:24 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1svCZf-0000000GUEV-1ycp; Mon, 30 Sep 2024 09:20:12 +0000 X-UUID: 2e7899387f0d11efba0aef63c0775dbf-20240930 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=yqgHKnptu5bK43gGLrnEqqpfwTrlY1ULN7Za2e2rfGM=; b=anWrLSmYD1+3k4rZ20foGTgJzeg6I44Xk67A341xP3ORVfqRKoi8pGVGkxWaURuSVjuekGi6Z0EUyNn+KXIZ09mhSpR63EfBAJBf+rKr5nKi7Uezx0YUJx62hqUNx5SWlNo4OsuGdOrcbe1LkOn3n3qydIk+UcIm7JxT08CJIHo=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.41,REQID:e4ec411c-d2e9-4226-9037-edc61dcb945e,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:6dc6a47,CLOUDID:8cbcc89e-8e9a-4ac1-b510-390a86b53c0a,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:0,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_SNR X-UUID: 2e7899387f0d11efba0aef63c0775dbf-20240930 Received: from mtkmbs10n1.mediatek.inc [(172.21.101.34)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1650050316; Mon, 30 Sep 2024 02:20:06 -0700 Received: from mtkmbs11n1.mediatek.inc (172.21.101.185) by mtkmbs11n1.mediatek.inc (172.21.101.185) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Mon, 30 Sep 2024 17:20:03 +0800 Received: from mszsdhlt06.gcn.mediatek.inc (10.16.6.206) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Mon, 30 Sep 2024 17:20:02 +0800 From: Liankun Yang To: , , , , , , , , , , , , , CC: , , , , Subject: [PATCH v1 1/1] drm/mediatek: Add return value check when reading DPCD Date: Mon, 30 Sep 2024 17:17:41 +0800 Message-ID: <20240930092000.5385-1-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-20240930_022011_551265_0AA66251 X-CRM114-Status: GOOD ( 12.93 ) 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: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver") Signed-off-by: Liankun Yang --- 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 d8796a904eca..3cab65345d1e 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -2018,6 +2018,7 @@ 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; @@ -2032,7 +2033,12 @@ 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;