From patchwork Mon Nov 22 18:33:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Timo Aaltonen X-Patchwork-Id: 1558220 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4HybYy06hbz9sXS for ; Tue, 23 Nov 2021 05:35:50 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1mpEAC-0000zX-Kp; Mon, 22 Nov 2021 18:35:36 +0000 Received: from smtp-relay-canonical-0.internal ([10.131.114.83] helo=smtp-relay-canonical-0.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1mpE90-0007PB-9Y for kernel-team@lists.ubuntu.com; Mon, 22 Nov 2021 18:34:22 +0000 Received: from leon.. (mobile-user-c1d2e5-215.dhcp.inet.fi [193.210.229.215]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-0.canonical.com (Postfix) with ESMTPSA id 0398F40079 for ; Mon, 22 Nov 2021 18:34:21 +0000 (UTC) From: Timo Aaltonen To: kernel-team@lists.ubuntu.com Subject: [PATCH 08/30] drm/amd/display: Skip DPCD read for DPTX-to-DPIA hop Date: Mon, 22 Nov 2021 20:33:56 +0200 Message-Id: <20211122183418.73674-9-tjaalton@ubuntu.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211122183418.73674-1-tjaalton@ubuntu.com> References: <20211122183418.73674-1-tjaalton@ubuntu.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Jimmy Kizito BugLink: https://bugs.launchpad.net/bugs/1951868 [why & how] Driver does not need to train the first hop. Reviewed-by: Jun Lei Acked-by: Wayne Lin Acked-by: Nicholas Kazlauskas Acked-by: Harry Wentland Signed-off-by: Jimmy Kizito Signed-off-by: Alex Deucher (cherry picked from commit 31cf79f05d34f4a8040bbeaaf7f03b0fb5fe117f) Signed-off-by: Timo Aaltonen --- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c index c132fd8feaaf..a1eb5e2d4816 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c @@ -1433,6 +1433,13 @@ enum dc_status configure_lttpr_mode_non_transparent( if (encoding == DP_8b_10b_ENCODING) { repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt); + + /* Driver does not need to train the first hop. Skip DPCD read and clear + * AUX_RD_INTERVAL for DPTX-to-DPIA hop. + */ + if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA) + link->dpcd_caps.lttpr_caps.aux_rd_interval[--repeater_cnt] = 0; + for (repeater_id = repeater_cnt; repeater_id > 0; repeater_id--) { aux_interval_address = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 + ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (repeater_id - 1));