Hi Saravana, On Fri, Dec 18, 2020 at 4:34 AM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > Cyclic dependencies in some firmware was one of the last remaining > reasons fw_devlink=on couldn't be set by default. Now that cyclic > dependencies don't block probing, set fw_devlink=on by default. > > Setting fw_devlink=on by default brings a bunch of benefits (currently, > only for systems with device tree firmware): > * Significantly cuts down deferred probes. > * Device probe is effectively attempted in graph order. > * Makes it much easier to load drivers as modules without having to > worry about functional dependencies between modules (depmod is still > needed for symbol dependencies). > > If this patch prevents some devices from probing, it's very likely due > to the system having one or more device drivers that "probe"/set up a > device (DT node with compatible property) without creating a struct > device for it. If we hit such cases, the device drivers need to be > fixed so that they populate struct devices and probe them like normal > device drivers so that the driver core is aware of the devices and their > status. See [1] for an example of such a case. > > [1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@xxxxxxxxxxxxxx/ > Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx> Shimoda-san reported that next-20210111 and later fail to boot on Renesas R-Car Gen3 platforms. No output is seen, unless earlycon is enabled. I have bisected this to commit e590474768f1cc04 ("driver core: Set fw_devlink=on by default"). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
