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 Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4B909CA0FED for ; Tue, 9 Sep 2025 04:23:19 +0000 (UTC) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id 6DFA880422; Tue, 9 Sep 2025 06:23:17 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="syJYxzG9"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id 352FC80422; Tue, 9 Sep 2025 06:23:16 +0200 (CEST) Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id 9376A82A9E for ; Tue, 9 Sep 2025 06:23:12 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=sumit.garg@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 6F2916013C; Tue, 9 Sep 2025 04:23:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 747E9C4CEF4; Tue, 9 Sep 2025 04:23:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757391791; bh=8UQai/vt5N0MEUKyCFKhGVGeYmm7Rc6zTesgUdxh0go=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=syJYxzG9gCN3+GT0pS7Ssz3wlxzJkEkZmBNTGtOg5jt4+YGR1yMA0KB4Gnf8rhpmS VGeY+168c+oBqa4lxFfpeC27Dq7smt0P5rh9AdJnVqR5c96LubQ6TmMRM1cavASxSk Uun+bE3iVjzbkq/2hsVc25uv9Cc8YRBEAx7dXq4cp3j6OC2uJurifeRbNmIKnsOpzp t14IixBnkNB84DScdqjl79IexijnPuH2vCGaR4s1el8WUXQUbzl6oGltflAywiqpQK iUqp+pcLLTgb1KrzTvos7DdHDRKCyqkQmxh42DEXyIj9FQ9iRnGVPRKyE+bBHbqL0r 6MP14A+k/c2GQ== Date: Tue, 9 Sep 2025 09:53:04 +0530 From: Sumit Garg To: Stephan Gerhold Cc: Casey Connolly , Neil Armstrong , Tom Rini , Sam Day , u-boot-qcom@groups.io, u-boot@lists.denx.de Subject: Re: [PATCH v2 0/6] Fix UART autoboot issues on DragonBoard 410c Message-ID: References: <20250908-db410c-autoboot-fixes-v2-0-316ed98e0143@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250908-db410c-autoboot-fixes-v2-0-316ed98e0143@linaro.org> X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.39 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.103.8 at phobos.denx.de X-Virus-Status: Clean On Mon, Sep 08, 2025 at 01:31:20PM +0200, Stephan Gerhold wrote: > There have been issues with autoboot on DB410c for years, where autoboot > gets interrupted by spurious input on the UART console. I've tried fixing > this back in 2021, but it turned out this fix was not enough. Looking into > it further, there are two separate issues to fix: > > - Spurious input with UART disconnected: The RX pin is floating in this > case, resulting in garbage or a UART break event (0x00 byte). This is > interpreted as input in the autoboot prompt. Fix this by adding > bias-pull-up for the RX pin. I've made this change upstream in Linux > 6.16 for all MSM8916/MSM8939 devices and it has already landed in U-Boot > through the recent subtree update of dts/upstream. > > - Spurious input when querying console size with UART connected: It's > unclear why this happens, but it seems to be some issue in the overly > complex implementation of 4-character packing mode in the serial_msm > driver. Fix this by switching the driver to use the more simple > single-character mode, which doesn't have this issue. > > With these patches, autoboot is finally working reliably on DragonBoard > 410c (and hopefully will remain so for the future :-)). > > Signed-off-by: Stephan Gerhold > --- > Changes in v2: > - Rebase on top of U-Boot master and fix conflicts > - Drop backported upstream DT changes (already landed through recent > subtree merge of DT changes in Linux 6.16) > - Link to v1: https://lore.kernel.org/r/20250624-db410c-autoboot-fixes-v1-0-d96c97ae41d1@linaro.org Nice fixes and cleanup, FWIW: Acked-by: Sumit Garg -Sumit > > --- > Stephan Gerhold (6): > board: dragonboard410c: Drop now unneeded bootph-all for console > Revert "serial: serial_msm: Delay initialization to let pins stabilize" > serial: msm: Cleanup register naming > serial: msm: Reset after writing to DMEN > serial: msm: Re-enable after resetting > serial: msm: Use single character mode > > arch/arm/dts/apq8016-sbc-u-boot.dtsi | 9 --- > drivers/serial/serial_msm.c | 127 ++++++++--------------------------- > 2 files changed, 29 insertions(+), 107 deletions(-) > --- > base-commit: 328747974a0620d0996113fe2b3906b06e96de00 > change-id: 20250419-db410c-autoboot-fixes-ad7f4f5973a8 > > Best regards, > -- > Stephan Gerhold >