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 41841C27C4F for ; Tue, 18 Jun 2024 16:40:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0yJM0ovOkN6GK5Bd8SBBgPGoyqQCrIxqepYNCbNI5Is=; b=yNSygeqS9A/PB8UajuVNFuKbMc fjjRiRUe4vxdoI778yxuyban3Pzx7uxXDDxm1MOjkW5oXuhWpzP50DBGebGmzz8LY2fJvkBmFtjEJ OGg+e2cXGYc58UgZiBCxGSGenwMVBRNHZrzjSWMxOQNLjLK3e+uHL2TlzPS8Ek87uzcDxqNEfutVK utK5pyzu8ITAigz7WmiTh+JARzIG8+TGNxXrvlAwBG2wmWNdk2ZyFxVmMdeE66zQTLTYAe83jgr1I zdKNyM/bceJFxfgYGGaspZ7rvV32uP+IemZDR9QjE+BxBNqgSq+N5ExfrtT45Z4YLE8tclPf9bZUE AKYVwc1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sJbsq-0000000FtAJ-3GCl; Tue, 18 Jun 2024 16:40:36 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sJbsk-0000000Ft9T-0WP6 for linux-arm-kernel@lists.infradead.org; Tue, 18 Jun 2024 16:40:33 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0659ADA7; Tue, 18 Jun 2024 09:40:53 -0700 (PDT) Received: from bogus (unknown [10.57.89.235]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 99DC73F6A8; Tue, 18 Jun 2024 09:40:26 -0700 (PDT) Date: Tue, 18 Jun 2024 17:40:24 +0100 From: Sudeep Holla To: Will Deacon Cc: Prarit Bhargava , lpieralisi@kernel.org, Sudeep Holla , guohanjun@huawei.com, Liu Wei , catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, liuwei09.cestc.cn@cecloud.com, rafael@kernel.org Subject: Re: [PATCH] ACPI: Do not enable ACPI SPCR console by default on arm64 Message-ID: <20240618164024.tehpbscax47jkluj@bogus> References: <20240530015332.7305-1-liuwei09@cestc.cn> <20240618152923.GB2354@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240618152923.GB2354@willie-the-truck> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240618_094030_338460_44FB8BBB X-CRM114-Status: GOOD ( 30.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 18, 2024 at 04:29:24PM +0100, Will Deacon wrote: > On Thu, May 30, 2024 at 09:06:17AM -0400, Prarit Bhargava wrote: > > On 5/29/24 21:53, Liu Wei wrote: > > > Consistency with x86 and loongarch, don't enable ACPI SPCR console > > > by default on arm64 > > > > > > Signed-off-by: Liu Wei > > > --- > > > arch/arm64/kernel/acpi.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > > > index dba8fcec7f33..1deda3e5a0d2 100644 > > > --- a/arch/arm64/kernel/acpi.c > > > +++ b/arch/arm64/kernel/acpi.c > > > @@ -227,7 +227,8 @@ void __init acpi_boot_table_init(void) > > > if (earlycon_acpi_spcr_enable) > > > early_init_dt_scan_chosen_stdout(); > > > } else { > > > - acpi_parse_spcr(earlycon_acpi_spcr_enable, true); > > > + /* Do not enable ACPI SPCR console by default */ > > > + acpi_parse_spcr(earlycon_acpi_spcr_enable, false); > > > if (IS_ENABLED(CONFIG_ACPI_BGRT)) > > > acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt); > > > } > > > > It's been a while, and the status of arm hardware may have changed. IIRC the > > choice to force enable this is that most arm hardware is headless and this > > was a _required_ option for booting. > > > > I'm not sure if that's still the case as it's been a long time. > > > > Can anyone from the ARM community provide an approval here? > > I don't have a strong opinion either way, but adding the Arm ACPI folks > in case they care. > > Having said that, if the only rationale for this patch is consistency > with other architectures, then I think I'd lean towards leaving the > behaviour as-is so we don't give users a nasty surprise on their next > kernel upgrade. > +1, I am concerned about breaking existing behaviour on the platforms in the wild. Also many platforms running ACPI would have already used console cmdline parameter if SPCR is not their choice for the console. So I don't see the need to align with other arch default behaviour here, we can revisit if someone shouts with a real reason as why cmdline option is not viable. -- Regards, Sudeep