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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 364E8C04EBF for ; Thu, 15 Nov 2018 09:56:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 08CD0223CB for ; Thu, 15 Nov 2018 09:56:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08CD0223CB 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 S2388002AbeKOUDL (ORCPT ); Thu, 15 Nov 2018 15:03:11 -0500 Received: from mail.bootlin.com ([62.4.15.54]:34349 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728609AbeKOUDL (ORCPT ); Thu, 15 Nov 2018 15:03:11 -0500 Received: by mail.bootlin.com (Postfix, from userid 110) id 0926820D72; Thu, 15 Nov 2018 10:56:02 +0100 (CET) Received: from localhost (aaubervilliers-681-1-13-146.w90-88.abo.wanadoo.fr [90.88.134.146]) by mail.bootlin.com (Postfix) with ESMTPSA id CA62C20741; Thu, 15 Nov 2018 10:55:51 +0100 (CET) Date: Thu, 15 Nov 2018 10:55:51 +0100 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@lists.freedesktop.org, Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, Michael Trimarchi , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, linux-amarula@amarulasolutions.com Subject: Re: [PATCH v4 08/26] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation Message-ID: <20181115095551.uctdkfmuwlnzhjnn@flea> References: <20181113111633.20189-1-jagan@amarulasolutions.com> <20181113111633.20189-9-jagan@amarulasolutions.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="cw633pztpuimj6kk" Content-Disposition: inline In-Reply-To: <20181113111633.20189-9-jagan@amarulasolutions.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --cw633pztpuimj6kk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Tue, Nov 13, 2018 at 04:46:15PM +0530, Jagan Teki wrote: > The horizontal and vertical back porch calculation in BSP > code is simply following the Linux drm comment diagram, in > include/drm/drm_modes.h which is >=20 > [hv]back porch =3D [hv]total - [hv]sync_end >=20 > BSP code form BPI-M64-bsp is calculating vertical back porch as > (from linux-sunxi/drivers/video/sunxi/disp2/disp/de/disp_lcd.c) >=20 > timmings->ver_sync_time=3D panel_info->lcd_vspw; > timmings->ver_back_porch=3D panel_info->lcd_vbp-panel_info->lcd_vspw; >=20 > vbp =3D panel->lcd_vbp; > vspw =3D panel->lcd_vspw; > dsi_dev[sel]->dsi_basic_size0.bits.vbp =3D vbp-vspw; > dsi_dev[sel]->dsi_basic_size0.bits.vbp =3D panel->lcd_vbp - panel->lcd_vs= pw; > =3D> timmings->ver_back_porch + panel_info->lcd_vspw - panel_info->lcd_v= spw > =3D> timmings->ver_back_porch > =3D> mode->vtotal - mode->end >=20 > Which evatually same as mode->vtotal - mode->vsync_end so update the > same in SUN6I_DSI_BASIC_SIZE0_VBP >=20 > On the information note, existing SUN6I_DSI_BASIC_SIZE0_VSA is proper > value. >=20 > Signed-off-by: Jagan Teki I've tested your changes on my A33 board, and this commit will break it. It creates vblank timeouts, and visual artifacts at the bottom of the display. Later commits seem to fix the issue, but will create some blanking on the upper third of the display. Since the documentation is quite sparse, and a MIPI-DSI analyzer is way too expensive, I'd really like to have at least what each of these commits are actually fixing, and what symptoms each of these were causing, and not just "the BSP does it". Having some datasheet for the panels you had working would help too. Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --cw633pztpuimj6kk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCW+1CpwAKCRDj7w1vZxhR xRksAP0VayJ3BucsWPpkUNCLS5uSpu0Y/UmHQJI6zYlOOw1O+QD/WG6DY2TRtgZx SkX1FYI9osX19IGL7yPL2/NHRlTVSQo= =zMmg -----END PGP SIGNATURE----- --cw633pztpuimj6kk--