From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97D67606A31A for ; Sun, 25 Oct 2026 07:04:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=puri.sm header.i=@puri.sm header.a=rsa-sha256 header.s=smtp2 header.b=imsWa+T3 Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DB72E10E762; Sun, 25 Oct 2026 07:04:23 +0000 (UTC) X-Greylist: delayed 540 seconds by postgrey-1.36 at gabe; Sun, 25 Oct 2026 07:04:16 UTC Received: from ms.puri.sm (ms.puri.sm [135.181.196.210]) by gabe.freedesktop.org (Postfix) with ESMTPS id AC5DA10E762 for ; Sun, 25 Oct 2026 07:04:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=puri.sm; s=smtp2; t=1792911314; bh=w71AOpYV4KpXNAjp5dKcP/PzJQbMMVW/4xVNb5ORZE4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=imsWa+T3NwRKj8oDtY5T56XNFve2MS+TUd02sJYs5aeVoSrQDQy4zZ8UUbXRqWOB9 kmBbKYJcREts1A6Ub3FykMs/zZT4RbOkFz3rF4f9nhxEDKGZgG6JzwQf8rfVHwqjiV feInWMkQ6iXChh8Qi2JJLmsXORXxEo1ELGeco6LaXPdtM501mq/ED6rBJtQQ7/LbJB HLS9qTS387y90wDm4ti1z28sy72ZCOt+3XXeaTukVOzdnJVQFpgsFSkdLQBg9raZNm XyynV6FouwPU7AU8okfXdkmzdCr3uwHaTKxsJfqHcJZqWa9QikBh/3lO31Z2ExhLvR 6PvDQvTS62Unw== Received: from pliszka.localnet (83.24.9.32.ipv4.supernova.orange.pl [83.24.9.32]) by ms.puri.sm (Postfix) with ESMTPSA id 1F7131F6F8; Sat, 24 Oct 2026 23:55:13 -0700 (PDT) From: Sebastian Krzyszkowiak To: Esben Haabendal Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Guido =?UTF-8?B?R8O8bnRoZXI=?= , Fabio Estevam , Robert Chiras , Sam Ravnborg , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, "Oliver F. Brown" Subject: Re: [PATCH RESEND v4 4/4] drm/bridge: nwl-dsi: Correct MIPI DSI horizontal sync timing Date: Sun, 25 Oct 2026 07:55:10 +0100 Message-ID: In-Reply-To: <20261014-nwl-dsi-fixes-v4-4-b9138ea5e12c@geanix.com> References: <20261014-nwl-dsi-fixes-v4-0-b9138ea5e12c@geanix.com> <20261014-nwl-dsi-fixes-v4-4-b9138ea5e12c@geanix.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "dri-devel" X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On =C5=9Broda, 14 pa=C5=BAdziernika 2026 09:44:45 czas =C5=9Brodkowoeuropej= ski standardowy=20 Esben Haabendal wrote: > The NWL MIPI Host controller registers specifies the horizontal front > porch, sync pulse, and back porch in DSI packet payload size in bytes (ie. > not in pixel clocks). >=20 > The calculation for this is (mostly) described in section 13.6.3.5.1.2 of > the i.MX 8M Dual/8M QuadLite/8M Quad Applications Processors Reference > Manual (rev. 3.1). The formula shown there does not take packet header si= ze > into account though. >=20 > The formula implemented here converts the hfp, hsa, and hbp to DSI packet > bytes and then subtracts the number of packet header bytes. >=20 > It is worth noting that these values only needs to match approximately, > according to the reference manual. >=20 > Based on commit in NXP vendor tree > commit f2a61699749d ("LF-7981-4: drm/bridge: nwl-dsi: Correct MIPI DSI > horizontal sync timing") >=20 > Signed-off-by: Esben Haabendal > Cc: Robert Chiras > Cc: Oliver F. Brown This lets the Librem 5 screen be driven without additional timing hacks. Tested-by: Sebastian Krzyszkowiak