From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B86FA357A34; Wed, 14 Jan 2026 21:06:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768424774; cv=none; b=HTTQKBIF0qWkA5IjzAjvWmF9XfB6WJVO+bcUovgyI3uuWoxzyDmTPmK6DUDbEZ3Bychah5UX6j1Ct8jlcJm9xXM0B/tzPkH7EaqGlOUd9hpcgjiZJb2bW78PkpNU+limYttCv5hTDdjl65+MtcF6MBV1neXoifB1sukVQ9XXdoE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768424774; c=relaxed/simple; bh=/olI7K1iCiuQwD+KYfd9LVc59nvrvfvQwRL9Amhn/no=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kAUY56ZnhPAfuPKQJjnMy0Hxoqt00+mJ+TniGdlZeXEJveS+UnIApEApQ0aHf2xFmb+gSiIAuy3VHJKa2emR9VKBaUmUFgmyooLoQVuMWCplZfGA7bf9OwPm+qMpPfJGjoovfV2QeLIu6Ay7+ZUOjfrmS9ta7ZLJ9aL6vmshax4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=foss.arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=foss.arm.com 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 8B0951515; Wed, 14 Jan 2026 13:06:05 -0800 (PST) Received: from bogus (unknown [10.57.49.158]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 172B23F59E; Wed, 14 Jan 2026 13:06:09 -0800 (PST) Date: Wed, 14 Jan 2026 21:06:06 +0000 From: Sudeep Holla To: Neil Armstrong Cc: Satya Durga Srinivasu Prabhala , Mark Rutland , Sudeep Holla , Lorenzo Pieralisi , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, trilok.soni@oss.qualcomm.com Subject: Re: [PATCH] firmware: smccc: default ARM_SMCCC_SOC_ID to disabled Message-ID: References: <20260112-disable_smccc_soc_id-v1-1-a5bee24befb4@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jan 14, 2026 at 06:12:29PM +0100, Neil Armstrong wrote: > On 1/13/26 07:24, Satya Durga Srinivasu Prabhala wrote: > > The ARM SMCCC SoC ID driver is currently enabled by default and publishes > > SMCCC-provided SoC identification into /sys/bus/soc/devices/socX/*. > > > > On platforms where a vendor SoC driver already exposes widely-consumed > > attributes (e.g. Qualcomm socinfo [1]), enabling the SMCCC driver changes > > the format of /sys/devices/soc0/soc_id (e.g. "jep106:XXYY:ZZZZ" instead > > of a vendor logical ID like "519") and breaks existing userspace consumers. > > > > Flip the default of CONFIG_ARM_SMCCC_SOC_ID from y to n. Platforms that > > prefer SMCCC over a vendor driver can explicitly enable it. > > > > This avoids unexpected format changes and keeps the generic SoC sysfs > > stable on systems that rely on vendor-specific identification. > > > > [1] > > Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/qcom/socinfo.c > > > > Signed-off-by: Satya Durga Srinivasu Prabhala > > --- > > drivers/firmware/smccc/Kconfig | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/firmware/smccc/Kconfig b/drivers/firmware/smccc/Kconfig > > index 15e7466179a6..f830d11ebdca 100644 > > --- a/drivers/firmware/smccc/Kconfig > > +++ b/drivers/firmware/smccc/Kconfig > > @@ -18,8 +18,11 @@ config HAVE_ARM_SMCCC_DISCOVERY > > config ARM_SMCCC_SOC_ID > > bool "SoC bus device for the ARM SMCCC SOC_ID" > > depends on HAVE_ARM_SMCCC_DISCOVERY > > - default y > > + default n > > select SOC_BUS > > help > > Include support for the SoC bus on the ARM SMCCC firmware based > > platforms providing some sysfs information about the SoC variant. > > + Note: Several vendor platforms provide their own SoC information > > + drivers under drivers/soc/*. To avoid conflicting sysfs attribute > > + formats in /sys/devices/socX/*, this driver defaults to disabled. > > > > --- > > base-commit: b71e635feefc852405b14620a7fc58c4c80c0f73 > > change-id: 20260112-disable_smccc_soc_id-ed09ef4d777f > > > > Best regards, > > Disabling it by default impacts other platforms, the arm64 kernel is designed > to be generic and run on any platform with defconfig and from the same build, > please don't forget that. > > If you want to ship an arm64 kernel tailored for Qualcomm platforms, you're > allowed, and you're also allowed to disable ARM_SMCCC_SOC_ID. > Exactly! > The soc sysfs interface is designed to support multiple source of information, > from vendor (like qcom socinfo) and smccc ID. And this is well documented, > and pretty obvious... > Indeed, otherwise soc_device_register() would have failed for more than one calls to it if that was the design/intention. -- Regards, Sudeep