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 B2225C4167B for ; Fri, 1 Dec 2023 06:49:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377650AbjLAGtc (ORCPT ); Fri, 1 Dec 2023 01:49:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229654AbjLAGta (ORCPT ); Fri, 1 Dec 2023 01:49:30 -0500 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1FC11736 for ; Thu, 30 Nov 2023 22:49:35 -0800 (PST) Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 3B16nKwu090484; Fri, 1 Dec 2023 00:49:20 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1701413360; bh=8ir9SHgj+6BiqA15DG54/o7JpkjIT/ox3drhpYaelBs=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=bJpsq/nAffL13+7SKurJOWjnWoWsvZW//r8SUTHhqSd2q25K5tVZr4hchHNsxFYIa YytR7C4FLge0IKxOnoNt4s+aW2lo9JIKd1e+nr6GJHK94kPv3sOv+su1UwOJ0S5Pe7 A3RU7E9eUta8Mql5ELMXQpOdFM6rz1DewjhimBOg= Received: from DFLE115.ent.ti.com (dfle115.ent.ti.com [10.64.6.36]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 3B16nKa6014568 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 1 Dec 2023 00:49:20 -0600 Received: from DFLE101.ent.ti.com (10.64.6.22) by DFLE115.ent.ti.com (10.64.6.36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Fri, 1 Dec 2023 00:49:19 -0600 Received: from fllv0040.itg.ti.com (10.64.41.20) by DFLE101.ent.ti.com (10.64.6.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Fri, 1 Dec 2023 00:49:19 -0600 Received: from localhost (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by fllv0040.itg.ti.com (8.15.2/8.15.2) with ESMTP id 3B16nJTU075833; Fri, 1 Dec 2023 00:49:19 -0600 Date: Fri, 1 Dec 2023 00:49:19 -0600 From: Nishanth Menon To: Tony Lindgren CC: Francesco Dolcini , , , Arnd Bergmann , Vignesh Raghavendra , Catalin Marinas , Will Deacon , Tero Kristo Subject: Re: [PATCH] arm64: defconfig: increase SERIAL_8250_NR_UARTS Message-ID: <20231201064919.5mbmqo5fco7n3rgq@endnote> References: <20231130231657.12715-1-francesco@dolcini.it> <20231201060346.GE5169@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20231201060346.GE5169@atomide.com> X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 assume you are talking of arch/arm64/boot/dts/ti/k3-am62-verdin-wifi.dtsi which in turn uses arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi (5 uarts) and that is where the increase in serial port is coming from. Now 8 or 5 (which seems to be the relevant need) is subjective :( [1] https://lore.kernel.org/linux-arm-kernel/Y3x%2FcGYWLLB+J2zU@atomide.com/ -- Regards, Nishanth Menon Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D