Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757913AbeAICDi (ORCPT + 1 other); Mon, 8 Jan 2018 21:03:38 -0500 Received: from mail-pf0-f195.google.com ([209.85.192.195]:41128 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757780AbeAICDg (ORCPT ); Mon, 8 Jan 2018 21:03:36 -0500 X-Google-Smtp-Source: ACJfBosReGFOr89KDVnY99LSNylNgYVRy9TbpY/ReyXWvug5whBxwoyArR4DGxyGatDYsgPBRyrILw== From: Jonathan Liu To: Maxime Ripard , David Airlie , Chen-Yu Tsai Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@googlegroups.com, Jonathan Liu Subject: [PATCH v3 1/3] drm/sun4i: hdmi: Check for unset best_parent in sun4i_tmds_determine_rate Date: Tue, 9 Jan 2018 13:03:21 +1100 Message-Id: <20180109020323.11852-2-net147@gmail.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180109020323.11852-1-net147@gmail.com> References: <20180109020323.11852-1-net147@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: It is possible that if there is no exact rate match and "rounded = clk_hw_round_rate(parent, ideal)" gives high enough values (e.g. if rounded is 2 * ideal) that the condition "abs(rate - rounded / i) < abs(rate - best_parent / best_div)" is never met and best_parent is never set. This results in req->rate and req->best_parent_rate being assigned 0. To avoid this, we set best_parent to the first calculated rate if it is unset. The sun4i_tmds_calc_divider function already has a similar check. Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support") Signed-off-by: Jonathan Liu --- drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c index dc332ea56f6c..4d235e5ea31c 100644 --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c @@ -102,7 +102,7 @@ static int sun4i_tmds_determine_rate(struct clk_hw *hw, goto out; } - if (abs(rate - rounded / i) < + if (!best_parent || abs(rate - rounded / i) < abs(rate - best_parent / best_div)) { best_parent = rounded; best_div = i; -- 2.15.1