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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C66C1C433F5 for ; Wed, 10 Nov 2021 12:10:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4F9F60FED for ; Wed, 10 Nov 2021 12:10:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231879AbhKJMNd (ORCPT ); Wed, 10 Nov 2021 07:13:33 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24724 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232036AbhKJMNZ (ORCPT ); Wed, 10 Nov 2021 07:13:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636546228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Rr36Cb2Y1cvFR41scNcUzd8wBnS/OAi/NVPg1Fb83xQ=; b=WCyx7NqO0zlXbv6T1k6wAvWpEp6FQzDNQLjrfkV/D50aCWeubwxf7Gcq3OwYGqB9leNOar 1vLLczfzBhjW4EZP0sWFeenRkerdgpfK16FPVIAAZ7ucmEZ6miigGaJfr/4KgaZ7YrsxRK W5mKHpzf9Nhh0YocHN2blBLqb/DhVHU= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-598-daiFPBbkNeCOKiPMainlDw-1; Wed, 10 Nov 2021 07:10:27 -0500 X-MC-Unique: daiFPBbkNeCOKiPMainlDw-1 Received: by mail-ed1-f70.google.com with SMTP id i9-20020a508709000000b003dd4b55a3caso2122987edb.19 for ; Wed, 10 Nov 2021 04:10:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Rr36Cb2Y1cvFR41scNcUzd8wBnS/OAi/NVPg1Fb83xQ=; b=j1NiAw2AVvA2spygpaSUqjw6tqOYjvk3bFZeBE1j57WwsIJGUP7eRclKZBNd8RbJxg vnQ85WHtlnFtjVWcAcHlGSVLj6YPGz5eHhb6QbwCExibU20GLNX6lWRqLC9Awii08cah dXs4B9C8YBK3Tv5ZdlGT+cn4iaTlBh4n7LNMk8AdT36Ae5A1MnYaMsT2TyWulJpr2RGL eQA+g0mOy1p3NL13AGH90EBHCNPgUUCpPPv8IBq6/AHuEtlZm3wnAaS3tCn+RZtnHUWE C58z2D7EKoYq2vJ/B1rHQEnyz1pui/jUj76/d48Zc2WF6lXSSZGiGFZzA/QWiFzhNgHI 5nFg== X-Gm-Message-State: AOAM530zu39L87rUv5xkkq43ukCPNeI3TCLvaGXcYNnEn7f1AInEgji/ WO1JzbDofp3H6XdYx/6+PueNv5wLhFlgmvq8joSFHqZKpCWU1FIXISdLIKwgLuLH/+FVO09+96B px6sRDK0kmcYyWq2i2RrjaJkIFR/42H17Kr8a7H/k X-Received: by 2002:a17:906:ad89:: with SMTP id la9mr19787428ejb.178.1636546226126; Wed, 10 Nov 2021 04:10:26 -0800 (PST) X-Google-Smtp-Source: ABdhPJwf4XP8fkeIWWNmHm7LmReGjzuQX86h1/sC+gmwglVaX4WVJuIk3uu0SgugELXK3xZxJVQ9JlvsL+t5QFcdnjo= X-Received: by 2002:a17:906:ad89:: with SMTP id la9mr19787400ejb.178.1636546225940; Wed, 10 Nov 2021 04:10:25 -0800 (PST) MIME-Version: 1.0 References: <20211029201402.428284-1-wander@redhat.com> In-Reply-To: From: Wander Costa Date: Wed, 10 Nov 2021 09:10:14 -0300 Message-ID: Subject: Re: [PATCH] tty: serial: Use fifo in 8250 console driver To: Andy Shevchenko Cc: wander@redhat.com, Greg Kroah-Hartman , Jiri Slaby , "Maciej W. Rozycki" , Johan Hovold , Andrew Jeffery , "open list:SERIAL DRIVERS" , open list Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 1, 2021 at 12:33 PM Andy Shevchenko wrote: > > On Mon, Nov 1, 2021 at 5:22 PM Wander Costa wrote: > > Em s=C3=A1b., 30 de out. de 2021 04:41, Andy Shevchenko > > escreveu: > > > On Friday, October 29, 2021, wrote: > > ... > > > > I don't see any links. > > > > Oops, sorry about that. I must have accidentally deleted it while > > editing the commit message. > > Here it is https://github.com/walac/serial-console-test. > > I will update the patch with the link. > > Thanks! > > ... > > > > On how many different UARTs have you tested this? Have you tested oop= s and NMI contexts? > > > > > I only tested in a half dozen machines that I have available. I tried > > it in panic, warnings, IRQ contexts, etc. Theoretically, this change > > should not be affected by the context. Theoretically... > > > > > What I would like to say here is that the code is being used on zilli= ons of different 8250 implementations here and I would be rather skeptical = about enabling the feature for everyone. > > > > > I did my homework and studied the 16550 datasheets, but yes, there is > > always this risk. Maybe people more experienced with PC serial ports > > than me might think the patch is not worth the risk of breaking some > > unknown number of devices out there, and I am ok with that. It is a > > valid point. > > Here is a translation of my comment to a roadmap. > > 1. Introduce yet another UART quirk or capability (see corresponding > UART_CAP_* or UART_*_QUIRK definitions) > 2. Add your patch conditionally based on the above > 3. Enable it on UART(s) you _have tested_ > Thank you for the feedback, I submitted a v2 patch with your proposed chang= es, Cheers, Wander > -- > With Best Regards, > Andy Shevchenko >