From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C44433987 for ; Mon, 16 Oct 2023 18:14:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from gloria.sntech.de (gloria.sntech.de [185.11.138.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BB17EB for ; Mon, 16 Oct 2023 11:14:44 -0700 (PDT) Received: from i53875b5b.versanet.de ([83.135.91.91] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qsS6x-0007t7-TA; Mon, 16 Oct 2023 20:14:39 +0200 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Liu Ying Cc: neil.armstrong@linaro.org, conor+dt@kernel.org, rfoss@kernel.org, krzysztof.kozlowski+dt@linaro.org, jonas@kwiboo.se, shawnguo@kernel.org, s.hauer@pengutronix.de, jernej.skrabec@gmail.com, robh+dt@kernel.org, Laurent.pinchart@ideasonboard.com, andrzej.hajda@intel.com, kernel@pengutronix.de, linux-imx@nxp.com Subject: Re: [PATCH 5/9] drm/bridge: synopsys: dw-mipi-dsi: Use pixel clock rate to calculate lbcc Date: Mon, 16 Oct 2023 20:14:38 +0200 Message-ID: <1971539.CrzyxZ31qj@diego> In-Reply-To: <20230717061831.1826878-6-victor.liu@nxp.com> References: <20230717061831.1826878-1-victor.liu@nxp.com> <20230717061831.1826878-6-victor.liu@nxp.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_PASS, T_SPF_HELO_TEMPERROR autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Hi, Am Montag, 17. Juli 2023, 08:18:27 CEST schrieb Liu Ying: > To get better accuration, use pixel clock rate to calculate lbcc instead of > lane_mbps since the pixel clock rate is in KHz while lane_mbps is in MHz. > Without this, distorted image can be seen on a HDMI monitor connected with > i.MX93 11x11 EVK through ADV7535 DSI to HDMI bridge in 1920x1080p@60 video > mode. > > Signed-off-by: Liu Ying looks like I'm late to the party, but this change breaks the display output my px30 minievb with the xinpeng xpp055c272 dsi display [0]. Found this commit via git bisection and added a bit of debug output to compare the value differences for the old and new calculation: [ 34.810722] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 810 * 480 * 1000 / 8 [ 34.810749] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 810 * 64000 * 24 / (4 * 8) [ 34.810756] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 48600000, new lbcc: 38880000 [ 34.810762] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 10 * 480 * 1000 / 8 [ 34.810767] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 10 * 64000 * 24 / (4 * 8) [ 34.810773] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 600000, new lbcc: 480000 [ 34.810778] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 40 * 480 * 1000 / 8 [ 34.810783] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 40 * 64000 * 24 / (4 * 8) [ 34.810789] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 2400000, new lbcc: 1920000 With the new lbcc I get a blank dsi panel and just going back to the old calculation of lbcc restores the image. I don't have that much in-depth knowledge about dsi stuff and the original panel times also "just" came from the vendor tree, but I really would like to keep that display working ;-) . Do you have any idea which way to go to fix this? Thanks Heiko [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/rockchip/px30-evb.dts#n138 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/panel/panel-xinpeng-xpp055c272.c > --- > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > index c754d55f71d1..332388fd86da 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -762,8 +763,15 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi, > u32 hcomponent) > { > u32 frac, lbcc; > + int bpp; > > - lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8; > + bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); > + if (bpp < 0) { > + dev_err(dsi->dev, "failed to get bpp\n"); > + return 0; > + } > + > + lbcc = div_u64((u64)hcomponent * mode->clock * bpp, dsi->lanes * 8);