From patchwork Fri May 3 12:29:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 163313 Delivered-To: patch@linaro.org Received: by 2002:a92:7e86:0:0:0:0:0 with SMTP id q6csp546815ill; Fri, 3 May 2019 05:31:19 -0700 (PDT) X-Google-Smtp-Source: APXvYqyXH2ukdbSUxAg2dhv49Y43BVI/WlTB+guyBT59dTRqqyfELynzGCDlH9NWmsEiNDoTPRu/ X-Received: by 2002:a63:ed4f:: with SMTP id m15mr9981981pgk.387.1556886679552; Fri, 03 May 2019 05:31:19 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1556886679; cv=none; d=google.com; s=arc-20160816; b=Es9BI42DMflXIXaxwrlLqK2dZf1kkxCT5XXFJpqumLgTeBDuz1DBuvluSD9cwoMeHw NMMWc3eTVZcMs6x7PLHYlIFdT9oIaNear96qXOaNqB+VqJFIMeMs97EN2VWjI5Ih0zVG +nGEdlUWl3oD1OM94AOsTCzQb8B2Soe21Kep8zjqvkcuzaPi5bGbfad8OLroc73kyF2O Ec2febsr1swmAMtNvdeRd4E1OR0Lk/fug90v6modJsUSGRXKpdaH8VPspsgRuqjAX4Ky JINpr8pwZFL3bmbaqlGEg1e9vhjdSprKl4bOK8mdBNZ7DAUJu5ViZ05LN7+KajUYtiV/ umEw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:content-transfer-encoding:cc:list-subscribe :list-help:list-post:list-archive:list-unsubscribe:list-id :precedence:mime-version:references:in-reply-to:message-id:date :subject:to:from:delivered-to; bh=asNuEKTuhvZAhil1WKKLGQ0LOpCM7G03lV9nziiHOgc=; b=wPImucWrwOX/ddD/uU3H9+4+yDMpCb3RuOWI2tEtHe4rAXezDHJFGFLs1saadR2bSo a6WNRwy0Zg9/IjhdAHAokHWK1gtqCaL74LjPZgInnRo73R6z1X6n0Hf3kyBhlRU4bMfz GwttU3G8F6jsN2L8NujN/SuMqhet1gTJ5v4DgTYsCMtVIiasV7xjZkn7A2Gw4xRTff4c +ZPKn0Q53wxSqHYRQ4DrXB/Zp7PbcN0ps2AvWbGit/RmidNYeYt/s7dQ9BCsnUZV6jnQ iFJm1VOpg/TYMQU/So754aqzoC46b4L0qvuqd9jluNfR6IsgjcGQkCD/HMsTWlMKIH+2 SacA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of dri-devel-bounces@lists.freedesktop.org designates 2610:10:20:722:a800:ff:fe36:1795 as permitted sender) smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org; dmarc=fail (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Return-Path: Received: from gabe.freedesktop.org (gabe.freedesktop.org. [2610:10:20:722:a800:ff:fe36:1795]) by mx.google.com with ESMTPS id l71si663937pfb.250.2019.05.03.05.31.19 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 03 May 2019 05:31:19 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of dri-devel-bounces@lists.freedesktop.org designates 2610:10:20:722:a800:ff:fe36:1795 as permitted sender) client-ip=2610:10:20:722:a800:ff:fe36:1795; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of dri-devel-bounces@lists.freedesktop.org designates 2610:10:20:722:a800:ff:fe36:1795 as permitted sender) smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org; dmarc=fail (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0FCE189F07; Fri, 3 May 2019 12:31:18 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from lelv0142.ext.ti.com (lelv0142.ext.ti.com [198.47.23.249]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8642D89F03 for ; Fri, 3 May 2019 12:31:16 +0000 (UTC) Received: from fllv0035.itg.ti.com ([10.64.41.0]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id x43CVDgM032421; Fri, 3 May 2019 07:31:13 -0500 Received: from DFLE113.ent.ti.com (dfle113.ent.ti.com [10.64.6.34]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id x43CVDHK129022 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 3 May 2019 07:31:13 -0500 Received: from DFLE103.ent.ti.com (10.64.6.24) by DFLE113.ent.ti.com (10.64.6.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5; Fri, 3 May 2019 07:31:13 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5 via Frontend Transport; Fri, 3 May 2019 07:31:13 -0500 Received: from deskari.lan (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id x43CUYtw002029; Fri, 3 May 2019 07:31:11 -0500 From: Tomi Valkeinen To: Andrzej Hajda , Laurent Pinchart , Lucas Stach , Andrey Gusakov , Philipp Zabel , Andrey Smirnov , Peter Ujfalusi , Jyri Sarha , Benoit Parrot , Subject: [PATCHv3 14/23] drm/bridge: tc358767: use more reliable seq when finishing LT Date: Fri, 3 May 2019 15:29:40 +0300 Message-ID: <20190503122949.12266-15-tomi.valkeinen@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190503122949.12266-1-tomi.valkeinen@ti.com> References: <20190503122949.12266-1-tomi.valkeinen@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1556886673; bh=U51m7omCOf6jKJBgqpjPT5g+6TzTgrGcBPh2jxPT/Qg=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=TtTi6zE5kfaMcI7qnkd2Hz2pxi8kB0057O5hMPoOlEAFGrfUQjaXvXjeEi0nI9HN8 VU2E9BnZlt9MrmFmn2woC5DO+9DFs1KA2UShc/RJX9WIpLrn02rquDJwqaPHTt8h1Y UzqvJ7xKaumY3pyZ24Mk3dX9AzvujRTMjnVDQzt4= X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tomi Valkeinen Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" At the end of the link training, two steps have to be taken: 1) tc358767's LT mode is disabled by a write to DP0_SRCCTRL, and 2) Remove LT flag in DPCD 0x102. Toshiba's documentation tells to first write the DPCD, then modify DP0_SRCCTRL. In my testing this often causes issues, and the link disconnects right after those steps. If I reverse the steps, it works every time. There's a chance that this is DP sink specific, though, but as my testing shows this sequence to be much more reliable, let's change it. Signed-off-by: Tomi Valkeinen Reviewed-by: Andrzej Hajda --- drivers/gpu/drm/bridge/tc358767.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index ed348e09576a..87eb875e1174 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -961,6 +961,18 @@ static int tc_main_link_enable(struct tc_data *tc) if (ret) goto err; + /* + * Toshiba's documentation suggests to first clear DPCD 0x102, then + * clear the training pattern bit in DP0_SRCCTRL. Testing shows + * that the link sometimes drops if those steps are done in that order, + * but if the steps are done in reverse order, the link stays up. + * + * So we do the steps differently than documented here. + */ + + /* Clear Training Pattern, set AutoCorrect Mode = 1 */ + tc_write(DP0_SRCCTRL, tc_srcctrl(tc) | DP0_SRCCTRL_AUTOCORRECT); + /* Clear DPCD 0x102 */ /* Note: Can Not use DP0_SNKLTCTRL (0x06E4) short cut */ tmp[0] = tc->link.scrambler_dis ? DP_LINK_SCRAMBLING_DISABLE : 0x00; @@ -968,9 +980,6 @@ static int tc_main_link_enable(struct tc_data *tc) if (ret < 0) goto err_dpcd_write; - /* Clear Training Pattern, set AutoCorrect Mode = 1 */ - tc_write(DP0_SRCCTRL, tc_srcctrl(tc) | DP0_SRCCTRL_AUTOCORRECT); - /* Wait */ timeout = 100; do {