Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751608AbdLULWj (ORCPT ); Thu, 21 Dec 2017 06:22:39 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:40043 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751689AbdLULWd (ORCPT ); Thu, 21 Dec 2017 06:22:33 -0500 X-Google-Smtp-Source: ACJfBotVlACPgPVy5LVpueerfQyO9fGocsloKPwknlwfTDSe/YNtJm1kszUInWlh+hh8KyaSnDerig== From: Jonathan Liu To: Maxime Ripard , David Airlie , Chen-Yu Tsai Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, Jonathan Liu Subject: [PATCH] drm/sun4i: hdmi: Fix sun4i_tmds_determine_rate Date: Thu, 21 Dec 2017 22:24:11 +1100 Message-Id: <20171221112411.21550-1-net147@gmail.com> X-Mailer: git-send-email 2.15.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1340 Lines: 40 There are several issues in sun4i_tmds_determine_rate: - doesn't check if the best match was already set before comparing it with the enumerated parameters which could result in integer divide by zero - doesn't consider rate halving when determining closest match if it can't match the requested rate exactly - sets best_div to i which corresponds to rate halving when it should be set to j which corresponds to the divider Fix these issues. Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support") Signed-off-by: Jonathan Liu --- drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c index dc332ea56f6c..3ecffa52c814 100644 --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c @@ -102,10 +102,13 @@ static int sun4i_tmds_determine_rate(struct clk_hw *hw, goto out; } - if (abs(rate - rounded / i) < - abs(rate - best_parent / best_div)) { + if (!best_parent || + abs(rate - rounded / i / j) < + abs(rate - best_parent / best_half / + best_div)) { best_parent = rounded; - best_div = i; + best_half = i; + best_div = j; } } } -- 2.15.0