Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965468AbdLVJOc (ORCPT ); Fri, 22 Dec 2017 04:14:32 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42140 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756076AbdLVJFo (ORCPT ); Fri, 22 Dec 2017 04:05:44 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Anholt , Andrzej Hajda , Sasha Levin Subject: [PATCH 4.14 152/159] drm/vc4: Avoid using vrefresh==0 mode in DSI htotal math. Date: Fri, 22 Dec 2017 09:47:17 +0100 Message-Id: <20171222084631.899669900@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084623.668990192@linuxfoundation.org> References: <20171222084623.668990192@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1654 Lines: 43 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Anholt [ Upstream commit af2eca53206c59ce9308a4f5f46c4a104a179b6b ] The incoming mode might have a missing vrefresh field if it came from drmModeSetCrtc(), which the kernel is supposed to calculate using drm_mode_vrefresh(). We could either use that or the adjusted_mode's original vrefresh value. However, we can maintain a more exact vrefresh value (not just the integer approximation), by scaling by the ratio of our clocks. v2: Use math suggested by Andrzej Hajda instead. v3: Simplify math now that adjusted_mode->clock isn't padded. v4: Drop some parens. Signed-off-by: Eric Anholt Link: https://patchwork.freedesktop.org/patch/msgid/20170815234722.20700-2-eric@anholt.net Reviewed-by: Andrzej Hajda Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vc4/vc4_dsi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/vc4/vc4_dsi.c +++ b/drivers/gpu/drm/vc4/vc4_dsi.c @@ -866,7 +866,8 @@ static bool vc4_dsi_encoder_mode_fixup(s adjusted_mode->clock = pixel_clock_hz / 1000 + 1; /* Given the new pixel clock, adjust HFP to keep vrefresh the same. */ - adjusted_mode->htotal = pixel_clock_hz / (mode->vrefresh * mode->vtotal); + adjusted_mode->htotal = adjusted_mode->clock * mode->htotal / + mode->clock; adjusted_mode->hsync_end += adjusted_mode->htotal - mode->htotal; adjusted_mode->hsync_start += adjusted_mode->htotal - mode->htotal;