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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham 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 27A11C43381 for ; Tue, 19 Mar 2019 10:25:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00E8820828 for ; Tue, 19 Mar 2019 10:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727336AbfCSKZ1 (ORCPT ); Tue, 19 Mar 2019 06:25:27 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:47893 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726717AbfCSKZ1 (ORCPT ); Tue, 19 Mar 2019 06:25:27 -0400 X-Originating-IP: 90.88.22.102 Received: from localhost (aaubervilliers-681-1-80-102.w90-88.abo.wanadoo.fr [90.88.22.102]) (Authenticated sender: maxime.ripard@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 542CBE0011; Tue, 19 Mar 2019 10:25:21 +0000 (UTC) Date: Tue, 19 Mar 2019 11:25:20 +0100 From: Maxime Ripard To: Jagan Teki Cc: David Airlie , Daniel Vetter , Chen-Yu Tsai , Michael Turquette , Rob Herring , Mark Rutland , linux-arm-kernel , linux-kernel , linux-clk , dri-devel , devicetree , Michael Trimarchi , linux-amarula@amarulasolutions.com, linux-sunxi Subject: Re: [PATCH v8 01/15] drm/sun4i: dsi: Fix video start delay computation Message-ID: <20190319102520.ldgjtyzrphuib3td@flea> References: <20190311133637.18334-1-jagan@amarulasolutions.com> <20190311133637.18334-2-jagan@amarulasolutions.com> <20190311153734.izg44ijwqqh2vpxc@flea> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="4kxxtlmvi7tknwsq" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org --4kxxtlmvi7tknwsq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Mar 11, 2019 at 09:31:11PM +0530, Jagan Teki wrote: > On Mon, Mar 11, 2019 at 9:07 PM Maxime Ripard wrote: > > > > On Mon, Mar 11, 2019 at 07:06:23PM +0530, Jagan Teki wrote: > > > Vertical video start delay is computed by excluding vertical front > > > porch value from total vertical timings. > > > > > > This clearly confirmed from BSP code and here how it computed, > > > > > > (drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c) > > > u32 vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp; > > > => (panel->lcd_vt) - panel->lcd_y - (panel->lcd_vbp) > > > => (timmings->ver_front_porch + panel->lcd_vbp + panel->lcd_y) > > > - panel->lcd_y - (panel->lcd_vbp) > > > => timmings->ver_front_porch + panel->lcd_vbp + panel->lcd_y > > > - panel->lcd_y - panel->lcd_vbp > > > => timmings->ver_front_porch > > > > > > But the current driver is assuming it can exclude vertical front > > > porch along with vertical sync values from total vertical timings, > > > which resulting wrong start delay indeed wrong picture rendering > > > in the panel. > > > > Same story here: which panel, which datasheet, which "wrong picture > > rendering"? > > It's bananapi,s070wv20-ct16 DSI You're answering one out of three questions. > > > Example: timings, where it produces the issue. > > > { > > > .vdisplay = 600, > > > .vsync_start = 600 + 12, > > > .vsync_end = 600 + 12 + 2, > > > .vtotal = 600 + 12 + 2 + 21, > > > } > > > > Can you 100% trust those timings? > > ie. reason, I have given the Mainline timings [1]. The above timings > are wrongly mentioned actual timings are from [1] You're still answering partially here. Those timings are working for RGB, you have no proof that we need to make the same adjustments for DSI. > > > It produces the desired start delay value as 19 but the correct working > > > value should be 513. > > > > > > So, Fix it by computing proper video start delay. > > > > > > Fixes: 69006ef0ecb1 ("drm/sun4i: dsi: Change the start delay calculation") > > > Signed-off-by: Jagan Teki > > > --- > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 10 ++++++++-- > > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > index 62a508420227..8d6292c0158b 100644 > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > @@ -364,8 +364,14 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi, > > > static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi, > > > struct drm_display_mode *mode) > > > { > > > - u16 start = clamp(mode->vtotal - mode->vdisplay - 10, 8, 100); > > > - u16 delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start; > > > + u16 delay = mode->vtotal - (mode->vsync_start - mode->vdisplay); > > > + > > > + /** > > > + * BSP comment: > > > + * put start_delay to tcon. set ready sync early to dramfreq, > > > + * so set start_delay 1 > > > + */ > > > > That doesn't make any sense to me... What does it mean? > > Which is meaning as above stated as "BSP comment" from here[2] It doesn't matter where you took it from. If you cannot explain what happen, putting a random label that doesn't explain anything will not help. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --4kxxtlmvi7tknwsq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXJDDkAAKCRDj7w1vZxhR xU+WAP0bWohQTOy2V10s8wo9M2tCtIwFTHk6g2vFYaoClQVpdAEA48ghCZuiSvUd 2pSL7z54qV6CklWr3sxeK3Mixv1nwwI= =hFp+ -----END PGP SIGNATURE----- --4kxxtlmvi7tknwsq--