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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 36940C4167B for ; Fri, 1 Dec 2023 21:13:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6ejhRid4KkFSfpPiI+Uw535eRPUzVuXRzDEkYeEdQhc=; b=P2fsQSWxGi9WPY exZBYPnkFTaoEgzarolCQ2Rr7hrsrTHxk7rnfCGZQjQ/HPvfdMahsef4JxaFk+HJTWhNFQwOb+4fu w3L60/9VOijAfmPfGTfGOJ9lXeCo4jkLi0KCiR0m3Hmey9X3Z6QSn2KrEQInBOIQOIpZlxNZZy54Z mgfekRuRZ/NfNflxOrrE+6Q2AZ9MSnPAjwERAFtFRA5oIWVz1O2jq/tDR/Jnfxk9892woebXnH8Eg Y2yOCpYRHgYmmERjgjzqe5QQqF7MChlI/cyZLdM3asnSNwuLDFDZOf4505K1XG8LagXb/+XXFScBa 1CWqA6DaM58o1CZX68wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r9Aok-00EeB0-2l; Fri, 01 Dec 2023 21:12:58 +0000 Received: from mail11.truemail.it ([217.194.8.81]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1r9Aoh-00EeAY-0F; Fri, 01 Dec 2023 21:12:56 +0000 Received: from gaggiata.pivistrello.it (93-49-2-63.ip317.fastwebnet.it [93.49.2.63]) by mail11.truemail.it (Postfix) with ESMTPA id EEA78206C3; Fri, 1 Dec 2023 22:12:51 +0100 (CET) Received: from livingston (unknown [192.168.42.11]) by gaggiata.pivistrello.it (Postfix) with ESMTP id A8D997F9DD; Fri, 1 Dec 2023 22:12:51 +0100 (CET) Received: from pivi by livingston with local (Exim 4.96) (envelope-from ) id 1r9Aod-0001ot-1m; Fri, 01 Dec 2023 22:12:51 +0100 Date: Fri, 1 Dec 2023 22:12:51 +0100 From: Francesco Dolcini To: Heiko =?iso-8859-1?Q?St=FCbner?= Cc: Florian Fainelli , Francesco Dolcini , linux-rockchip@lists.infradead.org, Francesco Dolcini , linux-arm-kernel@lists.infradead.org, quentin.schulz@theobroma-systems.com, Heiko Stuebner Subject: Re: [PATCH] arm64: defconfig: Increase SERIAL_8250_NR_UARTS to 10 Message-ID: References: <20231201191228.343230-1-heiko@sntech.de> <4075500.2IRrRt1zHL@diego> <3923943.BzM5BlMlMQ@diego> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3923943.BzM5BlMlMQ@diego> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231201_131255_285177_B3129C3C X-CRM114-Status: GOOD ( 36.31 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On Fri, Dec 01, 2023 at 10:03:07PM +0100, Heiko St=FCbner wrote: > Am Freitag, 1. Dezember 2023, 21:56:27 CET schrieb Heiko St=FCbner: > > Hi, > > = > > Am Freitag, 1. Dezember 2023, 21:09:29 CET schrieb Francesco Dolcini: > > > On Fri, Dec 01, 2023 at 11:57:53AM -0800, Florian Fainelli wrote: > > > > +Francesco, > > > > = > > > > On 12/1/23 11:12, Heiko Stuebner wrote: > > > > > From: Heiko Stuebner > > > > > = > > > > > Boards using socs like the rk3588 can use up to 10 uarts, so the = default > > > > > of 4 is way too low. Therefore increase the maximum number to 10. > > > Do you have an actual need of 10, e.g. an existing board with 10 uarts > > > enabled supported by the mainline kernel? Just thinking at the last a= rm64 SoC I > > > am working with it should be 12 if we use this as a metric. > > = > > The rk3588 can do 10 (0-9), the board I'm working on is using up to uar= t7 (aka 8 uarts). > > Reasoning below in the 3rd paragraph. > > = > > = > > > > > SERIAL_8250_RUNTIME_UARTS on the other hand describes the number = of uart > > > > > data structures to prepare before registering them. This option c= an stay > > > > > at its default value of 4 since for one it can be changed via a b= oot > > > > > parameter 8250.nr_uarts but also since > > > > > commit 9d86719f8769 ("serial: 8250: Allow using ports higher than= SERIAL_8250_RUNTIME_UARTS") > > > > > = > > > > > the kernel can register uarts dynamically that are above the > > > > > SERIAL_8250_RUNTIME_UARTS threshold. > > > > > = > > > > > Signed-off-by: Heiko Stuebner > > > > = > > > > There is a competing patch set from Francesco being submitted as we= ll: > > > > https://lore.kernel.org/all/20231201171544.1901-1-francesco@dolcini= .it/ > > > > > > > > looks like some coordination is necessary. > > = > > Thanks Florian for catching this coincidence. > > = > > = > > > Yep, thanks Florian. > > > = > > > Heiko: should I include your needs in my patch? It looks like these a= re the > > > days of the 8250 uart, I sent my patch just one day before yours. > > = > > yeah, I was surprised by the time overlap as well. > > = > > After reading up on NR_UARTS and NR_RUNTIME_UARTS I opted for going with > > the maximum possible. > > = > > From what I understood, increasing the runtime-uart-number would incur > > overhead in terms of prepared data structures. But the core NR_UARTS > > only seems to limit the actual maximum number of uarts in the system. > > = > > With the somewhat recent patch named above, even those can still be > > registered without bad effects, so I opted with increasing the NR_UARTS > > to the maximum to expect at some point, least the next board then needs > > yet another patch. > > But left the runtime number alone to not create overhead. > > = > > = > > So TL;DR: > > I could live with the 8 from your original patch, but I guess would pre= fer > > going with a safer value, so the 10 or your 12 from above. > > = > > Because I guess if a controller is present, someone will use it > > eventually ;-). > = > and looking at other rk3588 boards the indiedroid-nova actually > uses the uart9 (aka the 10th uart) ;-) I think this is not relevant. It uses only 2 uart in total, it should just works with the actual config. Francesco _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip