From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 608263BD222; Tue, 17 Mar 2026 13:15:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773753353; cv=none; b=DG3AY0X18bCtS6V9fM0262hDXnFSeuaH2D3ept2ffM0u0HOBYsz6dLe66rv7PTaEMF+AhCrzKAkbkScyYonqDFBD7wBR/IKvT+k9bggiwfGONkfMa0E8iUVi+AcVAK63B6Xgc/yoaYkkcWDyW6ODL2DQK0HhMlaVoKKqqVH1yTc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773753353; c=relaxed/simple; bh=5nZD/FcMNt4uZFYZDvszux+r19D1DG31Ez9jrBisMrs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A7KhyxKOvCltL9mGMhff+avJW8PT2Cbo93nuL6nznbhIPjhl5OFDlDjxoWP5c++yIxXVEfLEBsMwQmx84bk1OENwQ2q1Tq1VcNbrrofuksySEWhHu7qLkD0EO7VarUivwjcXY1YbPIseIpGdEjis+ZWRmBRCNGNyAHw5ocbzhEQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R0ZP93nT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R0ZP93nT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BCE7C4CEF7; Tue, 17 Mar 2026 13:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773753353; bh=5nZD/FcMNt4uZFYZDvszux+r19D1DG31Ez9jrBisMrs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=R0ZP93nTdHCXXNWbXq4hTY7VUFPUvhc2XHbd1jxmO1kE6wDerqPHzph714mv0bvDv 9H8O5dYW2YC2NVzNPouhJnWx/sbXzT1QmRNC5BRVt3NqkOmczZRLOT5wnCbPsUnKWo /cUfuwdimmj7dTynqbt7sQ9rNleMAX6ZAUu/uAUSZe7StaVDfkOJaNV3mOMQAJteKk IN44ZwvWHh1KtNSDQynAWHR1jfxpgUlqQ5v7qt43WzS3znAt/VFBZDbG94mhuxhEd/ A/lut7hHvxSQ6ubHGNqD1/v3jqagmrworTLgqNEB0jvwVzPC8H4WC+kmJaqGD8oc5R zlrW2BsrQbJ4A== Date: Tue, 17 Mar 2026 14:15:50 +0100 From: Maxime Ripard To: Abel Vesa Cc: Brian Masney , Jonathan Corbet , Shuah Khan , Michael Turquette , Stephen Boyd , Abel Vesa , Hans de Goede , Saravana Kannan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org Subject: Re: [PATCH] clk: add new Kconfig to control default behavior of disabling unused clocks Message-ID: <20260317-notorious-classic-sunfish-d016d5@houat> References: <20260316-clk-ignore-unused-kconfig-v1-1-6e95a4fb0c94@redhat.com> <20260317-almond-leech-of-correction-2a2ef6@houat> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="myhkh7i27t265nwe" Content-Disposition: inline In-Reply-To: --myhkh7i27t265nwe Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH] clk: add new Kconfig to control default behavior of disabling unused clocks MIME-Version: 1.0 On Tue, Mar 17, 2026 at 02:14:25PM +0200, Abel Vesa wrote: > On 26-03-17 08:30:24, Maxime Ripard wrote: > > Hi, > >=20 > > On Mon, Mar 16, 2026 at 06:33:45PM -0400, Brian Masney wrote: > > > At the 2023 Linux Plumbers Conference in Richmond VA, there was a > > > discussion about how large number of systems need to boot with > > > clk_ignore_unused. Per the discussions at the conference, the existing > > > behavior in the clk core is broken, and there is a desire to complete= ly > > > remove this functionality. > >=20 > > Broken how? > >=20 > > clk_ignore_unused is to a point where it's seriously cargo-culted and > > documented as a silver bullet, when in reality it's just a debug tool > > for broken drivers, and the driver must be fixed. > >=20 > > But nobody is actually fixing it. > >=20 > > See > > https://fedoraproject.org/wiki/Changes/Automatic_DTB_selection_for_aarc= h64_EFI_systems#How_To_Test > > for example. The affected clock could be marked as CLK_IS_CRITICAL, and > > fedora wouldn't have to package anything, change anything, etc. But no, > > the problem is clk_ignore_unused. >=20 > Nope. Don't ever mark clocks as critical unless system crashes without > them. >=20 > Here is an example or why clocks cannot be marked as critical but need > to be kept by the clk_ignore_unused: display driver probes later. > If you mark it as critical you just made the clock stay enabled even > when display is off. >=20 > And this is just one example. Then use CLK_IGNORE_UNUSED. Maxime --myhkh7i27t265nwe Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCablUAQAKCRAnX84Zoj2+ dgqpAYD9t+HdEiNodlyi45QoAtfdOEX8SOIFgR3xj3iywNGFpEdhvpzlSz0L/U6j jeGoccYBewZfGkyqxJgMMZV1rnKrBuh+Z/lq/yoSeAu/BcXQfRQtnouuFkH26OJ5 sOs7rItUmQ== =T4Jw -----END PGP SIGNATURE----- --myhkh7i27t265nwe--