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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 CA5D6C282C8 for ; Mon, 28 Jan 2019 15:54:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B1F620855 for ; Mon, 28 Jan 2019 15:54:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548690875; bh=bMj8qaKxvY4JOO+wl57mbdcLXtMvn+gcpzQv/7F2XvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cFUgICpYHnSPzJd0peU2BZqy6FAAzk9zYm2jG1En9j3h9Sj/FSZHbsI1cBTSL9GSU xxJsrtx8FsTxGFDvrkzMuTPet5XSQONazeTSUI1IJjc496PAc9QdZPPRVcKWuD6DXX anI+3Yts4KjGD6Inu2D9wA5kzOtArKnc2o8VRAB0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729709AbfA1Pyd (ORCPT ); Mon, 28 Jan 2019 10:54:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:40626 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729294AbfA1Pya (ORCPT ); Mon, 28 Jan 2019 10:54:30 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A0F9020855; Mon, 28 Jan 2019 15:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548690870; bh=bMj8qaKxvY4JOO+wl57mbdcLXtMvn+gcpzQv/7F2XvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=If3cVqlvIZ6UztG/601o+B/zwrZ8SkNX4JiLKSGcfOgC9BDlgK+Qn7Y8jRPdJKYfI 8GJhMW06We5jcWikBH3Tz2mCDt/Tacm5N4MgNkzEDhHZNIFw8JDw8kXEBJKTekzF83 +h1Jibt6ms43jCGrY8e3j5hAjFwK9jOUCV5k1KZM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Paul Hsieh , Alex Deucher , Sasha Levin , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 4.20 218/304] drm/amd/display: Add retry to read ddc_clock pin Date: Mon, 28 Jan 2019 10:42:15 -0500 Message-Id: <20190128154341.47195-218-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128154341.47195-1-sashal@kernel.org> References: <20190128154341.47195-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paul Hsieh [ Upstream commit bd4905a9583c760da31ded7256dca6f71483c3dc ] [WHY] On customer board, there is one pluse (1v , < 1ms) on DDC_CLK pin when plug / unplug DP cable. Driver will read it and config DP to HDMI/DVI dongle. [HOW] If there is a real dongle, DDC_CLK should be always pull high. Try to read again to recovery this special case. Retry times = 3. Need additional 3ms to detect DP passive dongle(3 failures) Signed-off-by: Paul Hsieh Reviewed-by: Eric Yang Acked-by: Leo Li Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 23 ++++++++++++++----- 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index 5141c1401889..ef1b350a45e0 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -332,7 +332,7 @@ bool dc_link_is_dp_sink_present(struct dc_link *link) { enum gpio_result gpio_result; uint32_t clock_pin = 0; - + uint8_t retry = 0; struct ddc *ddc; enum connector_id connector_id = @@ -361,11 +361,22 @@ bool dc_link_is_dp_sink_present(struct dc_link *link) return present; } - /* Read GPIO: DP sink is present if both clock and data pins are zero */ - /* [anaumov] in DAL2, there was no check for GPIO failure */ - - gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin); - ASSERT(gpio_result == GPIO_RESULT_OK); + /* + * Read GPIO: DP sink is present if both clock and data pins are zero + * + * [W/A] plug-unplug DP cable, sometimes customer board has + * one short pulse on clk_pin(1V, < 1ms). DP will be config to HDMI/DVI + * then monitor can't br light up. Add retry 3 times + * But in real passive dongle, it need additional 3ms to detect + */ + do { + gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin); + ASSERT(gpio_result == GPIO_RESULT_OK); + if (clock_pin) + udelay(1000); + else + break; + } while (retry++ < 3); present = (gpio_result == GPIO_RESULT_OK) && !clock_pin; -- 2.19.1