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[73.183.52.120]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cda21484casm1462547685a.40.2026.03.17.08.00.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Mar 2026 08:00:39 -0700 (PDT) Date: Tue, 17 Mar 2026 11:00:37 -0400 From: Brian Masney To: Abel Vesa Cc: Maxime Ripard , 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: References: <20260316-clk-ignore-unused-kconfig-v1-1-6e95a4fb0c94@redhat.com> <20260317-almond-leech-of-correction-2a2ef6@houat> <20260317-notorious-classic-sunfish-d016d5@houat> <2dsd7hq4bn25dibqk62a7o56tt2tecf645tq3upccneq4hby67@cmjjc5d6ximt> Precedence: bulk X-Mailing-List: linux-doc@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: User-Agent: Mutt/2.3.0 (2026-01-25) On Tue, Mar 17, 2026 at 04:20:06PM +0200, Abel Vesa wrote: > On 26-03-17 10:13:08, Brian Masney wrote: > > FWIW, the only reason I posted this patch is because at the end of > > Stephen's LPC talk I got the impression that this was also an acceptable > > change. I'm fine with dropping this change. > > Here is the scenario that proves adding such config isn't the right > solution: think of single kernel image working with different SoCs from > different vendors. This is actually the case where distros need to have > a way to provide one kernel image + thousands of DTBs and be able to > boot one each one of the boards. Whatever this config is set to in the > kernel image, it will not work with all platforms. Agreed. However, with or without this new Kconfig, we have this problem today. Right now the kernel isn't bootable on large numbers of systems, and people have to manually add clk_ignore_unused. I agree though that we don't want to penalize boards that are doing things right, and have a full clock tree described with higher power draw. As a test, on my Thinkpad x13s (sc8280xp) clk_disable_unused on Fedora 43 turns off 96 clocks on this laptop! I can infer what some of the clocks do based on their names, however I'm not in Qualcomm, and some of these clocks I'm not entire sure which ones would need CLK_IGNORE_UNUSED. I got it down to a set of 7 possible clocks that may need that flag by excluding some classes of clocks, such as usb. Brian