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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 1E176C43461 for ; Mon, 5 Apr 2021 16:05:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE813613D8 for ; Mon, 5 Apr 2021 16:05:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242003AbhDEQFh (ORCPT ); Mon, 5 Apr 2021 12:05:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:56730 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242094AbhDEQEu (ORCPT ); Mon, 5 Apr 2021 12:04:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9529D613C5; Mon, 5 Apr 2021 16:04:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617638684; bh=3paG+NvRbAoLrk1/j8WNtE2Nni1aFGQaxISx6eaQlQs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FckgboDYRf0ni3tU0oAAZJoCEtx1E0iwWmuCq/Kygp+my7/KbLhHE5gw88kjjjvFH 13JNZQzQApSsGBnGcMutZiu7uKiJPwcwCGSZgNhbcR8cvbnG93Pk564nCzUh5GyNJZ dYYra4nlmdEUZNQxyeNMX4dO3cNLvbgxdDmadFlRKmnB6WbgbsXKxXUKNi+kxl5h97 jhnjH5+hLP8teC9Gmdt1Nf6fUcw41/qz286VtI6aiw0VrCaRjHmQFraPFXpskysNqN U+FLIw1zigfVRMcqlu0SuyJ3ae0wvMPYtrBfMunaVqu1UHP4BYBwiP/yJN772g9sVx MOY+ezlj8KwiA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dmitry Osipenko , Thierry Reding , Sasha Levin , dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 10/22] drm/tegra: dc: Don't set PLL clock to 0Hz Date: Mon, 5 Apr 2021 12:04:19 -0400 Message-Id: <20210405160432.268374-10-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210405160432.268374-1-sashal@kernel.org> References: <20210405160432.268374-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Osipenko [ Upstream commit f8fb97c915954fc6de6513cdf277103b5c6df7b3 ] RGB output doesn't allow to change parent clock rate of the display and PCLK rate is set to 0Hz in this case. The tegra_dc_commit_state() shall not set the display clock to 0Hz since this change propagates to the parent clock. The DISP clock is defined as a NODIV clock by the tegra-clk driver and all NODIV clocks use the CLK_SET_RATE_PARENT flag. This bug stayed unnoticed because by default PLLP is used as the parent clock for the display controller and PLLP silently skips the erroneous 0Hz rate changes because it always has active child clocks that don't permit rate changes. The PLLP isn't acceptable for some devices that we want to upstream (like Samsung Galaxy Tab and ASUS TF700T) due to a display panel clock rate requirements that can't be fulfilled by using PLLP and then the bug pops up in this case since parent clock is set to 0Hz, killing the display output. Don't touch DC clock if pclk=0 in order to fix the problem. Signed-off-by: Dmitry Osipenko Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/gpu/drm/tegra/dc.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c index b2c8c68b7e26..626d3cb2a915 100644 --- a/drivers/gpu/drm/tegra/dc.c +++ b/drivers/gpu/drm/tegra/dc.c @@ -1688,6 +1688,11 @@ static void tegra_dc_commit_state(struct tegra_dc *dc, dev_err(dc->dev, "failed to set clock rate to %lu Hz\n", state->pclk); + + err = clk_set_rate(dc->clk, state->pclk); + if (err < 0) + dev_err(dc->dev, "failed to set clock %pC to %lu Hz: %d\n", + dc->clk, state->pclk, err); } DRM_DEBUG_KMS("rate: %lu, div: %u\n", clk_get_rate(dc->clk), @@ -1698,11 +1703,6 @@ static void tegra_dc_commit_state(struct tegra_dc *dc, value = SHIFT_CLK_DIVIDER(state->div) | PIXEL_CLK_DIVIDER_PCD1; tegra_dc_writel(dc, value, DC_DISP_DISP_CLOCK_CONTROL); } - - err = clk_set_rate(dc->clk, state->pclk); - if (err < 0) - dev_err(dc->dev, "failed to set clock %pC to %lu Hz: %d\n", - dc->clk, state->pclk, err); } static void tegra_dc_stop(struct tegra_dc *dc) -- 2.30.2