From patchwork Fri Dec 13 23:45:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11291951 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AA552930 for ; Fri, 13 Dec 2019 23:46:27 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 89E0E24676 for ; Fri, 13 Dec 2019 23:46:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="dcKFlE9X" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89E0E24676 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0CB126EE20; Fri, 13 Dec 2019 23:46:26 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by gabe.freedesktop.org (Postfix) with ESMTPS id C1C9E6EE1B for ; Fri, 13 Dec 2019 23:46:13 +0000 (UTC) Received: by mail-pl1-x643.google.com with SMTP id bd4so1876673plb.8 for ; Fri, 13 Dec 2019 15:46:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+EeHRETkxu0picdlIzKsYQGsspaxhuZcBp2HnJGPsVI=; b=dcKFlE9XwzZl4mRXm1/nubZ9pM/vI36bs0JeNK8OmJeHbYVsGHdZYepNRVJ27sqRc8 hBJ40LIojZR/TpIta9y7LrW5GFl/dpxEH1+dISE61RwY2XZdnLh1/ZIv6XoYsVSE5+b2 5ynaQAh0YciRpY3C3TrKMakmgW3Wn/NaJtiGM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+EeHRETkxu0picdlIzKsYQGsspaxhuZcBp2HnJGPsVI=; b=SfBN5NVXodRJJxg0KWyd00VoE3HHvA91+Yu+sW5qELHRnYMTMl7ag2la8qmQgH2KsJ usH8IKK5bYXe+as+JsB0HHFVP5YojP0D1x/mNsdhM9yqATtB4ZV3dLO34PXVTKEBGvqd 3xgoR9FOrd2E5rzktPUipDygIHWCnelb27AS0g49uddpts1H9xi5Od6bAkyXxZgLFBSH e/+N5PjmM6RbzkZiK4jJFhm59vAHED056Dt5ek47HE8XuLHd1Wd4Aw09yYPVAb5IyAZ+ GdEotb9sXfFeWFpQdDWHurqHp6IqzmU0j1fapbHUS0ZNioTzINpj0ELX22/9WknVEQan GCdQ== X-Gm-Message-State: APjAAAXv3HjnbAmYhFzuB8U2mpIPA8Uz1IQk0YHHCerc0GfY44qKuuS2 myj1Wx0eAjP1UOu/CUx3JRFOTw== X-Google-Smtp-Source: APXvYqzwmXELCKHrbQ5y46SHZ0WNh/wWcubb9wd3jDnndYX/iS4e3gFT+K2H5pXNZA1dmILWpcEWAg== X-Received: by 2002:a17:90a:2569:: with SMTP id j96mr2373833pje.79.1576280773362; Fri, 13 Dec 2019 15:46:13 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id z19sm12282905pfn.49.2019.12.13.15.46.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Dec 2019 15:46:12 -0800 (PST) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong Subject: [PATCH 8/9] drm/bridge: ti-sn65dsi86: Train at faster rates if slower ones fail Date: Fri, 13 Dec 2019 15:45:29 -0800 Message-Id: <20191213154448.8.I251add713bc5c97225200894ab110ea9183434fd@changeid> X-Mailer: git-send-email 2.24.1.735.g03f4e72817-goog In-Reply-To: <20191213234530.145963-1-dianders@chromium.org> References: <20191213234530.145963-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robdclark@chromium.org, Jernej Skrabec , Jonas Karlman , David Airlie , linux-arm-msm@vger.kernel.org, Douglas Anderson , dri-devel@lists.freedesktop.org, bjorn.andersson@linaro.org, seanpaul@chromium.org, Laurent Pinchart , linux-kernel@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" If we fail training at a lower DP link rate let's now keep trying until we run out of rates to try. Basically the algorithm here is to start at the link rate that is the theoretical minimum and then slowly bump up until we run out of rates or hit the max rate of the sink. We query the sink using a DPCD read. This is, in fact, important in practice. Specifically at least one panel hooked up to the bridge (AUO B116XAK01) had a theoretical min rate more than 1.62 GHz (if run at 24 bpp) and fails to train at the next rate (2.16 GHz). It would train at 2.7 GHz, though. Signed-off-by: Douglas Anderson --- drivers/gpu/drm/bridge/ti-sn65dsi86.c | 69 +++++++++++++++++++++++---- 1 file changed, 59 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 48fb4dc72e1c..cc8bef172f69 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -454,7 +454,7 @@ static const unsigned int ti_sn_bridge_dp_rate_lut[] = { 0, 1620, 2160, 2430, 2700, 3240, 4320, 5400 }; -static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) +static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn_bridge *pdata) { unsigned int bit_rate_khz, dp_rate_mhz; unsigned int i; @@ -472,8 +472,42 @@ static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz) break; - regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, - DP_DATARATE_MASK, DP_DATARATE(i)); + return i; +} + +static int ti_sn_bridge_get_max_dp_rate_idx(struct ti_sn_bridge *pdata) +{ + u8 data; + int ret; + + ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &data); + if (ret != 1) { + DRM_DEV_ERROR(pdata->dev, + "Can't read max rate (%d); assuming 5.4 GHz\n", + ret); + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; + } + + /* + * Return an index into ti_sn_bridge_dp_rate_lut. Just hardcode + * these indicies since it's not like the register spec is ever going + * to change and a loop would just be more complicated. Apparently + * the DP sink can only return these few rates as supported even + * though the bridge allows some rates in between. + */ + switch (data) { + case DP_LINK_BW_1_62: + return 1; + case DP_LINK_BW_2_7: + return 4; + case DP_LINK_BW_5_4: + return 7; + } + + DRM_DEV_ERROR(pdata->dev, + "Unexpected max data rate (%#x); assuming 5.4 GHz\n", + (int)data); + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; } static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata) @@ -530,13 +564,15 @@ static unsigned int ti_sn_get_max_lanes(struct ti_sn_bridge *pdata) return data & DP_LANE_COUNT_MASK; } -static int ti_sn_link_training(struct ti_sn_bridge *pdata) +static int ti_sn_link_training(struct ti_sn_bridge *pdata, int dp_rate_idx, + const char **last_err_str) { unsigned int val; int ret; /* set dp clk frequency value */ - ti_sn_bridge_set_dp_rate(pdata); + regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, + DP_DATARATE_MASK, DP_DATARATE(dp_rate_idx)); /* enable DP PLL */ regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1); @@ -545,7 +581,7 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) val & DPPLL_SRC_DP_PLL_LOCK, 1000, 50 * 1000); if (ret) { - DRM_ERROR("DP_PLL_LOCK polling failed (%d)\n", ret); + *last_err_str = "DP_PLL_LOCK polling failed"; goto exit; } @@ -556,9 +592,9 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) val == ML_TX_NORMAL_MODE, 1000, 500 * 1000); if (ret) { - DRM_ERROR("Training complete polling failed (%d)\n", ret); + *last_err_str = "Training complete polling failed"; } else if (val == ML_TX_MAIN_LINK_OFF) { - DRM_ERROR("Link training failed, link is off\n"); + *last_err_str = "Link training failed, link is off"; ret = -EIO; } @@ -573,6 +609,9 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) static void ti_sn_bridge_enable(struct drm_bridge *bridge) { struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge); + const char *last_err_str; + int dp_rate_idx; + int max_dp_rate_idx; unsigned int val; int ret; @@ -616,9 +655,19 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge) regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK, val); - ret = ti_sn_link_training(pdata); - if (ret) + /* Train until we run out of rates */ + max_dp_rate_idx = ti_sn_bridge_get_max_dp_rate_idx(pdata); + for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata); + dp_rate_idx <= max_dp_rate_idx; + dp_rate_idx++) { + ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str); + if (!ret) + break; + } + if (ret) { + DRM_DEV_ERROR(pdata->dev, "%s (%d)\n", last_err_str, ret); return; + } /* config video parameters */ ti_sn_bridge_set_video_timings(pdata);