Re: [PATCH] clk: add new Kconfig to control default behavior of disabling unused clocks

Brian Masney
2026-03-17T15:00:45Z

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