From nobody Tue Dec 16 12:22:32 2025 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 D7608C4167B for ; Fri, 1 Dec 2023 19:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379564AbjLAT5a (ORCPT ); Fri, 1 Dec 2023 14:57:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379538AbjLAT5a (ORCPT ); Fri, 1 Dec 2023 14:57:30 -0500 Received: from mail11.truemail.it (mail11.truemail.it [IPv6:2001:4b7e:0:8::81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1ED52D54 for ; Fri, 1 Dec 2023 11:57:36 -0800 (PST) Received: from gaggiata.pivistrello.it (93-49-2-63.ip317.fastwebnet.it [93.49.2.63]) by mail11.truemail.it (Postfix) with ESMTPA id 66A11221C6; Fri, 1 Dec 2023 20:57:34 +0100 (CET) Received: from livingston (unknown [192.168.42.11]) by gaggiata.pivistrello.it (Postfix) with ESMTP id 194BF7F9C0; Fri, 1 Dec 2023 20:57:34 +0100 (CET) Received: from pivi by livingston with local (Exim 4.96) (envelope-from ) id 1r99dl-0001Hk-35; Fri, 01 Dec 2023 20:57:33 +0100 From: Francesco Dolcini To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Arnd Bergmann , Nishanth Menon , Vignesh Raghavendra Cc: Francesco Dolcini , Catalin Marinas , Will Deacon , Tero Kristo , Tony Lindgren Subject: [PATCH v3] arm64: defconfig: increase SERIAL_8250_NR_UARTS Date: Fri, 1 Dec 2023 20:57:32 +0100 Message-Id: <20231201195732.4931-1-francesco@dolcini.it> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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"). The need to increase this value was noticed while working with Toradex Verdin AM62, this board has 4 serial UART instances available to the user plus an internal one that is connected to a Bluetooth module. Without this change the fifth UART connected to the BT module is not instantiated and BT is not working. Instead of increasing the number to the bare minimum (5) that would be required to solve this specific issue, we increase this to 8 which seems a more reasonable number to have in the defconfig and should cover more valid use cases. With this change the kernel image size increases by ~3.2kB. bloat-o-meter summary: add/remove: 1/1 grow/shrink: 7/0 up/down: 3220/-8 (3212) Cc: Tony Lindgren Reviewed-by: Tony Lindgren Signed-off-by: Francesco Dolcini --- v2: added details in the commit message on the verdin am62 uart config and requirement v3: added details on the kernel size increase because of this change --- arch/arm64/configs/defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index b60aa1f89343..ecd365cd1d87 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -448,6 +448,7 @@ CONFIG_SERIO_AMBAKMI=3Dy CONFIG_LEGACY_PTY_COUNT=3D16 CONFIG_SERIAL_8250=3Dy CONFIG_SERIAL_8250_CONSOLE=3Dy +CONFIG_SERIAL_8250_NR_UARTS=3D8 CONFIG_SERIAL_8250_EXTENDED=3Dy CONFIG_SERIAL_8250_SHARE_IRQ=3Dy CONFIG_SERIAL_8250_BCM2835AUX=3Dy --=20 2.39.2