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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT 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 A32ADC64E93 for ; Sat, 29 Sep 2018 13:53:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B97C20895 for ; Sat, 29 Sep 2018 13:53:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B97C20895 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728265AbeI2UVh convert rfc822-to-8bit (ORCPT ); Sat, 29 Sep 2018 16:21:37 -0400 Received: from mail.bootlin.com ([62.4.15.54]:54564 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728202AbeI2UVh (ORCPT ); Sat, 29 Sep 2018 16:21:37 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id EB59120787; Sat, 29 Sep 2018 15:53:01 +0200 (CEST) Received: from localhost (unknown [212.145.226.70]) by mail.bootlin.com (Postfix) with ESMTPSA id ACC0820734; Sat, 29 Sep 2018 15:53:01 +0200 (CEST) Date: Sat, 29 Sep 2018 15:53:02 +0200 From: Maxime Ripard To: Jagan Teki Cc: Chen-Yu Tsai , Icenowy Zheng , Jernej Skrabec , Vasily Khoruzhick , Rob Herring , Mark Rutland , Catalin Marinas , Will Deacon , David Airlie , dri-devel , Michael Turquette , Stephen Boyd , linux-clk , Michael Trimarchi , linux-arm-kernel , devicetree , linux-kernel , linux-sunxi Subject: Re: [PATCH 06/12] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation Message-ID: <20180929135302.ymdzapz5npvapti2@flea> References: <20180927114850.24565-1-jagan@amarulasolutions.com> <20180927114850.24565-7-jagan@amarulasolutions.com> <20180927152126.vovnvwmqdfpuxgdm@flea> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 27, 2018 at 09:50:34PM +0530, Jagan Teki wrote: > On Thu, Sep 27, 2018 at 8:51 PM Maxime Ripard wrote: > > > > On Thu, Sep 27, 2018 at 05:18:44PM +0530, Jagan Teki wrote: > > > According to horizontal and vertical timings are defined > > > per the diagram from include/drm/drm_modes.h > > > > > > Back porch = [hv]total - [hv]sync_end > > > > > > So, update SUN6I_DSI_BASIC_SIZE0_VBP calculation as > > > mode->vtotal - mode->vsync_end > > > > > > Signed-off-by: Jagan Teki > > > --- > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > index 1c7e42015645..599284971ab6 100644 > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > @@ -526,8 +526,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, > > > regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE0_REG, > > > SUN6I_DSI_BASIC_SIZE0_VSA(mode->vsync_end - > > > mode->vsync_start) | > > > - SUN6I_DSI_BASIC_SIZE0_VBP(mode->vsync_start - > > > - mode->vdisplay)); > > > + SUN6I_DSI_BASIC_SIZE0_VBP(mode->vtotal - > > > + mode->vsync_end)); > > > > Is it purely theoretical, or did you find some source that back that? > > VSA is done as per that, sync_end - sync start would give sync time. That's a different register though. > VBP also done in BPI-M64-bsp[1] which results back porch existing code > results fron porch. > > [1] https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c#L955 That code does back porch - sync length. Such a calculation doesn't make much sense as is, but you're saying that it results in the front porch. Again, what makes you say that? Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com