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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 7ECE3C43613 for ; Mon, 24 Jun 2019 14:23:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 534BA208E4 for ; Mon, 24 Jun 2019 14:23:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561386203; bh=s1BB5HhDmAE0uDrE0qpsPr949Sr8A4LFp811VtlPlQE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=cVzxX4Ysv7UKS9lGcJb3uZRKupPc0waJO2cQBzn6wNZ2iBFc2ctfZ9e68cPhGi0wH UTwuofH4e1kusj+Z5Jjh9YHFU47i9RFr91CF8RPJt4nnoOplOgJ0S7ANEy61FopAOm X6m6/w+h182JoIiSVRKUqIfjP51pTBIu1d96uSzU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728231AbfFXOXW (ORCPT ); Mon, 24 Jun 2019 10:23:22 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:39776 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727170AbfFXOXW (ORCPT ); Mon, 24 Jun 2019 10:23:22 -0400 Received: by mail-lj1-f195.google.com with SMTP id v18so12794230ljh.6; Mon, 24 Jun 2019 07:23:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=hGHNzjTTkC7XSqkNKO0Dj0BBPmg9DOd1ASPbbQfSUIQ=; b=a6mvrtETWDQIoQzNQzaG0r1m0wNREjXOUvKP8YgKSrXgH7IWnax57HEEUp6QnAX2Zw 0v28Crv6RfnaMnDg3wxi73ufOqCIu3IsGjifIiZ6WFyTOTN2pre4L6vIP30YyY4G2oJ/ Knt2HknmHYH+JfkbptJh4I51oNNWGxm9tKtWc0G9iGJx06qsjjWBf0Ty1vRkfiiT58/c fTgToj6iRFdpPhKMVF3S59jMdRDBIvi8jDZlPQxXXEP1XDkjBt767vrDE3ftcEiT+5+O t74HZargsBE4m49XNOB6CRoM75Pk3gOld8T4J2m+6fYXHV7NOMQs5pH9aFwIQJOzL6ie RriQ== X-Gm-Message-State: APjAAAWzCuH7w4SBR5mGs7VPwYJnvLU0OnScdHnHXDoLQjODp3+Pr78p 5ObT8GUSsbSSkBMVXI1kJxg= X-Google-Smtp-Source: APXvYqxQFnqLSlWHbgblNv8zbvjH5AV2mWcwcU0h0Y8jlXvW2YH/P7kGeDL2xDiHxr1mKCDpUpmNMw== X-Received: by 2002:a2e:8793:: with SMTP id n19mr1094836lji.174.1561386199989; Mon, 24 Jun 2019 07:23:19 -0700 (PDT) Received: from xi.terra (c-74bee655.07-184-6d6c6d4.bbcust.telenor.se. [85.230.190.116]) by smtp.gmail.com with ESMTPSA id m17sm1784222lfb.9.2019.06.24.07.23.19 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Jun 2019 07:23:19 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.92) (envelope-from ) id 1hfPsN-0003Iw-QI; Mon, 24 Jun 2019 16:23:19 +0200 Date: Mon, 24 Jun 2019 16:23:19 +0200 From: Johan Hovold To: Shyam Saini Cc: linux-serial@vger.kernel.org, Kernelnewbies , linux-usb@vger.kernel.org Subject: Re: junk character issue on minicom and screen Message-ID: <20190624142319.GB14667@localhost> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Mon, Jun 24, 2019 at 02:57:34PM +0530, Shyam Saini wrote: > Hello everyone, > > I'm working on Rockchip rk3399 Nanopc t4 board and I'm trying get > serial output from board using minicom and my board has baudrate > 1500000. > > I'm using a usb to serial converter. So, when i power on my board > minicom starts to give junk characters. > Minicom version: 2.7.1 > USB driver probed : cp210x > > But when I use the same setup with my colleagues laptop it gives > correct output (kernel version 4.15.0-52-generic ). > > Note that my colleague and i used same setup > Same usb driver probed > Same power adapter > same usb to serial converter wire > same minicom version. > same baudrate > > Other thing which i tried is switching kernel version and it turns out > that one of the older distro kernel on my system (debian 4.9.0-5-amd64 > ) is working fine and it seems like there is something changed in > newer kernel vesions. > Here is the quick summary > 4.19.0-4-amd64 -> not working > 4.15.0-52-generic -> working > 4.9.0-5-amd64 -> working > 5.2.0-rc4+ -> not working Thanks for the report. There were some changes between 4.15 and 4.19 related to the line speed handling which may have broken something in your setup. Do you know which variant of cp210x you have? Can your provide the output of lsusb -v? Also if you can run driver with debugging enabled when connecting the device and setting the line speed, that may give a clue about what is going on. For example, echo module cp210x =p > /sys/kernel/debug/dynamic_debug/control Does 115200 bps still work by the way? Johan