Hi Marc, On Mon, Jan 18, 2021 at 6:59 PM Marc Zyngier <maz@xxxxxxxxxx> wrote: > On 2021-01-18 17:39, Geert Uytterhoeven wrote: > > 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"). > > There is a tentative patch from Saravana here[1], which works around > some issues on my RK3399 platform, and it'd be interesting to find > out whether that helps on your system. > > Thanks, > > M. > > [1] > https://lore.kernel.org/r/20210116011412.3211292-1-saravanak@xxxxxxxxxx Thanks for the suggestion, but given no devices probe (incl. GPIO providers), I'm afraid it won't help. [testing] Indeed. With the debug prints in device_links_check_suppliers enabled, and some postprocessing, I get: 255 supplier e6180000.system-controller not ready 9 supplier fe990000.iommu not ready 9 supplier fe980000.iommu not ready 6 supplier febd0000.iommu not ready 6 supplier ec670000.iommu not ready 3 supplier febe0000.iommu not ready 3 supplier e7740000.iommu not ready 3 supplier e6740000.iommu not ready 3 supplier e65ee000.usb-phy not ready 3 supplier e6570000.iommu not ready 3 supplier e6054000.gpio not ready 3 supplier e6053000.gpio not ready As everything is part of a PM Domain, the (lack of the) system controller must be the culprit. What's wrong with it? It is registered very early in the boot: [ 0.142096] rcar_sysc_pd_init:442: of_genpd_add_provider_onecell() returned 0 Thanks! 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
