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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DCE6C4167B for ; Fri, 1 Dec 2023 15:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379449AbjLAPcB (ORCPT ); Fri, 1 Dec 2023 10:32:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379398AbjLAPb4 (ORCPT ); Fri, 1 Dec 2023 10:31:56 -0500 Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E902C10F9 for ; Fri, 1 Dec 2023 07:31:59 -0800 (PST) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 4A7665C00E0; Fri, 1 Dec 2023 10:31:59 -0500 (EST) Received: from imap51 ([10.202.2.101]) by compute5.internal (MEProxy); Fri, 01 Dec 2023 10:31:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm3; t=1701444719; x=1701531119; bh=S2 3umPlXJQkeulBSJ4NyHT/ySrJcetJwnTwa7Bmt//A=; b=GCgnEJblV3NjK6qiRz 12TBLKwVjPHyT8xGbs8zmQj5y0esR77HR2kGT2V0uIyEQHQT2Ld43Ty53uK0xboW ram+ZE6/UWM7J0H8XOGgqDXV348NO00EHdFhe+NyQ0k8F2Eo1oGiKi6Rot27IjWy rvmGuhvs2ggvVnD1xKuKGh1XAiXVvFWGh6quY7Ws7elg/IC3HeGwMYCxqN6ZhiKF 9har4YLSuV17ig6Snm7+9aZQJECTbzAcQkDW3EX4FEqBBryKwSOPxi1qNGXI+65N v4NwOCWIOnK24U4Sig4i/mCLg9TTXAFOur8aPOOqxUVH2P0OVRJ6UZVInzoZ6Jk0 6+HA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm1; t=1701444719; x=1701531119; bh=S23umPlXJQkeu lBSJ4NyHT/ySrJcetJwnTwa7Bmt//A=; b=M7Y6Tzi3+CtpLrklENV7GZQkfjvn6 ox3arxwg7QfZfqEiqVSRAiKkxON6U/B6KtOq25nh7u2gsRk6X21TLfScB0n5B+jP TZg3OuOQEpgc9JSR6HvfF+98BItPKJdu+jq464u/ShCZ3qQJm0tLNRYzhjg7+GrQ 9uQqoPYwxvxMXRReepRBvk28dNXcfRicat8gyczobRxaatYY1Xg1CDeYIprS3Je8 aOcDXGgWtBBotix2rcNKMvnGQKIAvPVLhB4/50rqvqlEMciCFYC8FvFZ3c43XFSh OkEpa5YApTWtulyQZcvOA4By9K3L7gBz0+TUTqjJOKa9v5o7piRDFi6Rw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvkedrudeiledgjeekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepffehueegteeihfegtefhjefgtdeugfegjeelheejueethfefgeeghfektdek teffnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 8A674B60089; Fri, 1 Dec 2023 10:31:58 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-1178-geeaf0069a7-fm-20231114.001-geeaf0069 MIME-Version: 1.0 Message-Id: <855dfa50-a3a3-415a-8612-4da59f995ef0@app.fastmail.com> In-Reply-To: <20231201064919.5mbmqo5fco7n3rgq@endnote> References: <20231130231657.12715-1-francesco@dolcini.it> <20231201060346.GE5169@atomide.com> <20231201064919.5mbmqo5fco7n3rgq@endnote> Date: Fri, 01 Dec 2023 16:31:38 +0100 From: "Arnd Bergmann" To: "Nishanth Menon" , "Tony Lindgren" Cc: "Francesco Dolcini" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Vignesh Raghavendra" , "Catalin Marinas" , "Will Deacon" , "Tero Kristo" Subject: Re: [PATCH] arm64: defconfig: increase SERIAL_8250_NR_UARTS Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 1, 2023, at 07:49, Nishanth Menon wrote: > On 08:03-20231201, Tony Lindgren wrote: >> * Francesco Dolcini [231130 23:17]: >> > Increase CONFIG_SERIAL_8250_NR_UARTS from 4 to 8, the current legacy value >> > is not adequate for embedded systems that use SoCs where it's common to >> > have a large number of serial ports. >> > >> > No need to change CONFIG_SERIAL_8250_RUNTIME_UARTS, see commit 9d86719f8769 >> > ("serial: 8250: Allow using ports higher than SERIAL_8250_RUNTIME_UARTS"). >> > >> > This enables using the UART connected Bluetooth device on Verdin AM62 >> > board. >> >> OK makes sense for distro use. >> >> Disabling unused ports leads into port names shifting, which we still can't >> easily tolerate until we have the DEVNAME:0.0 style addressing available for >> ports. So for now we still depend CONFIG_SERIAL_8250_NR_UARTS, eventually >> that too should become just a legacy ISA port array.. Meanwhile: >> >> Reviewed-by: Tony Lindgren > > I'd prefer to get Arnd's view on the topic as well (I kind of > recollect some historic discussion which I am not failing to trace > that there usage model doesn't exceed 4 and aliases could be used to > map these as required for the platform). The 8250 debate has been > popping on and off over the years.. Sigh.. memories of [1] still haunt > me. I don't recall any reason to have the limit set to the default of 4, other than possibly using excessive amounts of .data in vmlinux, but we have other serial port drivers that just hardcode a much larger value. Arnd