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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF9FAC43331 for ; Mon, 11 Nov 2019 18:46:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C429221655 for ; Mon, 11 Nov 2019 18:46:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573497979; bh=4e9pxfGDU6RapcaX+QCh8nJXlA3vULm4getxnp/+7Jc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S3bAXl0W46XPSiHR32d+jbEUw0+XNUW/NjsbaoSWD6ZTnLHOC3IIIFJhD85bxRWFN yk3FgxsZVLISV3pJ/Sf+fsXxmh/QrDps+7LHtanaKAGOE/oRCyTdU+sYCpvxNnht3U wHjwcoQ/CwY7qLS657ofDg6dfS/h5/NKrrH884k4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729982AbfKKSqS (ORCPT ); Mon, 11 Nov 2019 13:46:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:38692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729977AbfKKSqP (ORCPT ); Mon, 11 Nov 2019 13:46:15 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D129720659; Mon, 11 Nov 2019 18:46:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573497974; bh=4e9pxfGDU6RapcaX+QCh8nJXlA3vULm4getxnp/+7Jc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mT1NK2d6mQqvqmJte7Pmwichh1Cyf4FgsXZIewnXHvi7nUsyrHMb9MOrh7sfCG1jp cuGsbu6mpvAlq1GZw1T4++gyjT9kPOS3Huf8QHq1oEbwgAn5YaCwpZNI8/x+X/tiDe N9hSe+KG/Crk1MCx1p1fT/0MHCpd0iGhR+VMg/F0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Strauss , Tony Cheng , Leo Li , Alex Deucher , Sasha Levin Subject: [PATCH 4.19 111/125] drm/amd/display: Passive DP->HDMI dongle detection fix Date: Mon, 11 Nov 2019 19:29:10 +0100 Message-Id: <20191111181454.612373790@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191111181438.945353076@linuxfoundation.org> References: <20191111181438.945353076@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Strauss [ Upstream commit bc2fde42e2418808dbfc04de1a6da91d7d31cf1a ] [WHY] i2c_read is called to differentiate passive DP->HDMI and DP->DVI-D dongles The call is expected to fail in DVI-D case but pass in HDMI case Some HDMI dongles have a chance to fail as well, causing misdetection as DVI-D [HOW] Retry i2c_read to ensure failed result is valid Signed-off-by: Michael Strauss Reviewed-by: Tony Cheng Acked-by: Leo Li Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- .../gpu/drm/amd/display/dc/core/dc_link_ddc.c | 24 ++++++++++++++----- 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c index 8def0d9fa0ff0..46c9cb47a96e5 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c @@ -433,6 +433,7 @@ void dal_ddc_service_i2c_query_dp_dual_mode_adaptor( enum display_dongle_type *dongle = &sink_cap->dongle_type; uint8_t type2_dongle_buf[DP_ADAPTOR_TYPE2_SIZE]; bool is_type2_dongle = false; + int retry_count = 2; struct dp_hdmi_dongle_signature_data *dongle_signature; /* Assume we have no valid DP passive dongle connected */ @@ -445,13 +446,24 @@ void dal_ddc_service_i2c_query_dp_dual_mode_adaptor( DP_HDMI_DONGLE_ADDRESS, type2_dongle_buf, sizeof(type2_dongle_buf))) { - *dongle = DISPLAY_DONGLE_DP_DVI_DONGLE; - sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_DVI_MAX_TMDS_CLK; + /* Passive HDMI dongles can sometimes fail here without retrying*/ + while (retry_count > 0) { + if (i2c_read(ddc, + DP_HDMI_DONGLE_ADDRESS, + type2_dongle_buf, + sizeof(type2_dongle_buf))) + break; + retry_count--; + } + if (retry_count == 0) { + *dongle = DISPLAY_DONGLE_DP_DVI_DONGLE; + sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_DVI_MAX_TMDS_CLK; - CONN_DATA_DETECT(ddc->link, type2_dongle_buf, sizeof(type2_dongle_buf), - "DP-DVI passive dongle %dMhz: ", - DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000); - return; + CONN_DATA_DETECT(ddc->link, type2_dongle_buf, sizeof(type2_dongle_buf), + "DP-DVI passive dongle %dMhz: ", + DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000); + return; + } } /* Check if Type 2 dongle.*/ -- 2.20.1