On Tue, 08 Sep 2026, Mario Limonciello <[email protected]> wrote: > On 9/8/26 10:45, Jani Nikula wrote: >> On Mon, 07 Sep 2026, Mario Limonciello <[email protected]> wrote: >>> +/* Forward declaration for backlight_update_status */ >>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) >> >> I think IS_REACHABLE() is almost always a mistake. It's a hack to avoid >> link errors when something in a module needs something that is >> built-in. It's a combo that should be handled at Kconfig level, not at >> build level. >> >> BR, >> Jani. > > That came from this feedback from Thomas Zimmerman (I originally had it > as select: > > https://lore.kernel.org/dri-devel/[email protected]/ > > I was trying to use IS_REACHABLE to make it optional, but it sounds like > that's not the right direction then?
I agree with Thomas, but he's also not suggesting to use IS_REACHABLE()! The point is, if you express the dependencies properly with "depends on" in Kconfig, you won't need IS_REACHABLE(). It's the "select" that can lead to incorrect configurations, and IS_REACHABLE() is band-aid to work around this. BR, Jani. -- Jani Nikula, Intel
