From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B658B1EF955 for ; Wed, 13 Nov 2024 13:47:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731505651; cv=none; b=tCI6EQEabnfrjCI8H61HNm+YO3hVSrDyfmDx/SwQlAULwe4TzQQ/rbAO/EaaalbwcXuP+yx2YX0DA5kG408Bg6Ye6kjgOZpf1moAv8Bpa0TtMVeAxdTMfyZ0ZI5adVbL6sbnGO+0Up6cLAlVBCznnv14NGGPgLqKqSTNPk9rz64= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731505651; c=relaxed/simple; bh=X/qpTewFe4YwHFtx9JVnzn/Hz8SShkM9vR3bRa8jYs0=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=su8/xzPt3C7uGmQ9mJTicM56AweGlxpKtADr4Le/5pVjgllG8c1ONYLn+sB6kQv0vZScniw57NSQHDtMRtqXcEWyXv+ZEn7UMFQ15QO4KGprol4AUzKOpZSmHPaumrFRPrJRUz0tay6oMG92+qzRnW8Z8lGKcI2SjHBz46m4wg8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=cknow.org; spf=pass smtp.mailfrom=cknow.org; dkim=pass (2048-bit key) header.d=cknow.org header.i=@cknow.org header.b=oJAzufwb; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=cknow.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cknow.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cknow.org header.i=@cknow.org header.b="oJAzufwb" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cknow.org; s=key1; t=1731505643; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gHzgNJeIjaZvOxUJjdGqYlYVOhgCdeNHnJS5Tf5gqqo=; b=oJAzufwbQyl9R6AI9N6hKcQr1xZ7g917yk55W+o+iBq+F/6J8dDKSYoHOuGyXniCw1c0aH j1MELuP7eScci6PRS70Wd/QmT+lf9DJuovkNUfEEnAH9ktCkECh0Tdz07ow31JIM4+JO/x CMZEEqThq7seu+hjoeOoa6ddl5v5zGNuun1YOtZgCOKWRFZHEQy3VEyhKCIUC9nKu8PBJr roX7HkWwXJ7wF0RNlxSYpdfdoaGQ765LB1iTBqljN4lJ4fVhSVucFMVpXhH8ruHycyrNsa qIa51jRTdHN71BT7aANfTr4PV6dcC0yMiygo8gf0fEYLnVU61d33va7pud+cAw== Content-Type: multipart/signed; boundary=d6058cffb12ad5bd71cc704a8a30ec90289c25b15f02e290b59919e252dc; micalg=pgp-sha256; protocol="application/pgp-signature" Date: Wed, 13 Nov 2024 14:47:12 +0100 Message-Id: Cc: , , "Shawn Lin" Subject: Re: Q: Kconfig: 'If unsure, say N' X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Diederik de Haas" To: "Sudeep Holla" References: <20241112054623.7zxte2nny7h4st3h@bogus> In-Reply-To: <20241112054623.7zxte2nny7h4st3h@bogus> X-Migadu-Flow: FLOW_OUT --d6058cffb12ad5bd71cc704a8a30ec90289c25b15f02e290b59919e252dc Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Thanks for your response. On Tue Nov 12, 2024 at 6:46 AM CET, Sudeep Holla wrote: > On Fri, Nov 08, 2024 at 03:39:30PM +0100, Diederik de Haas wrote: > > In quite a number of Kconfig help text entries I see this: > > "If unsure, say N." > > > > But that raises the question: How can I be sure? > > If you don't know about the feature and it is not having any user-interfa= ce > why do you want to enable it. You must understand the feature to enable i= t > and use it IMO. Ok, understood. > You seem to contradict yourself here. If you have understood the help > text and think it is useful, it seems to me as an indication that you > are not unsure really. So you can enable it if you want TBH. > > > Not to discuss these specifically, but just for illustration: > > ``drivers/firmware/arm_scmi/transports/Kconfig`` has this > > option: ``ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE`` > > which IIUC enables an *optional* feature for an atomic transaction. > > > > "If you want the SCMI SMC based transport to operate in atomic > mode, avoiding any kind of sleeping behaviour for selected > transactions on the TX path, answer Y. > > Enabling atomic mode operations allows any SCMI driver using this > transport to optionally ask for atomic SCMI transactions and operate > in atomic context too, at the price of using a number of busy-waiting > primitives all over instead." > > So you read the above text, understood and find it useful. You must be > not unsure of this feature then, so what does that text bother you. In this case I was wondering whether this was related to Table 1 in "Power and Performance Management using Arm SCMI Specification" whitepaper. And I do think that I understand most of the Help text, but I'm not/less sure about the part starting with "at the price of ...". > It is just a caution to users who are just build and not looked at the > code, or have no idea about the feature or doesn't understand the help > text. And my question was exactly about "just a caution", which raises the question with me "caution for what?" ... which is an unspecified risk. So to be on the safe side, I will not enable modules with "If unsure, say N" unless I fully understand the source code. Cheers, Diederik --d6058cffb12ad5bd71cc704a8a30ec90289c25b15f02e290b59919e252dc Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQT1sUPBYsyGmi4usy/XblvOeH7bbgUCZzSt4wAKCRDXblvOeH7b boRiAQDx8Eh2ofEVih95M/okFMQsvSV2EcKZw8mMPdo8wV8lsgEA8/3y5avIppoN +/q44cpCGJSZQaSLsydKu9Uq+boaxQY= =qLuS -----END PGP SIGNATURE----- --d6058cffb12ad5bd71cc704a8a30ec90289c25b15f02e290b59919e252dc--