Hi, I'm adding a new driver and have an issue with Kconfig dependencies that I coulnd't sort out so far. Patch https://lore.kernel.org/patchwork/patch/1444212/ adds the new onboard_usb_hub driver which exports two functions, onboard_hub_create_pdevs() and onboard_hub_destroy_pdevs(). It also provides stubs for these functions which are used when the driver is not selected (CONFIG_USB_ONBOARD_HUB=n). The new exported functions are called by the xhci-plat driver (https://lore.kernel.org/patchwork/patch/1444215/). Since xhci-plat now depends on symbols from the onboard_hub_driver the following dependency was added to its Kconfig entry: config USB_XHCI_PLATFORM tristate "Generic xHCI driver for a platform device" select USB_XHCI_RCAR if ARCH_RENESAS + depends on USB_ONBOARD_HUB || !USB_ONBOARD_HUB This generally seems to work, however when USB_XHCI_PLATFORM is forced to be builtin by another driver that depends on it (e.g. USB_DWC3) it is still possible to build the onboard_hub driver as a module, which results in unresolved symbols: aarch64-linux-gnu-ld: drivers/usb/host/xhci-plat.o: in function `xhci_plat_remove': drivers/usb/host/xhci-plat.c:427: undefined reference to `onboard_hub_destroy_pdevs' drivers/usb/host/xhci-plat.c:427:(.text+0x82c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `onboard_hub_destroy_pdevs' aarch64-linux-gnu-ld: drivers/usb/host/xhci-plat.o: in function `xhci_plat_probe': drivers/usb/host/xhci-plat.c:379: undefined reference to `onboard_hub_create_pdevs' drivers/usb/host/xhci-plat.c:379:(.text+0x131c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `onboard_hub_create_pdevs' Kconfig generates the following warning with this configuration: WARNING: unmet direct dependencies detected for USB_XHCI_PLATFORM Depends on [m]: USB_SUPPORT [=y] && USB [=y] && USB_XHCI_HCD [=y] && (USB_ONBOARD_HUB [=m] || !USB_ONBOARD_HUB [=m]) Selected by [y]: - USB_DWC3 [=y] && USB_SUPPORT [=y] && (USB [=y] || USB_GADGET [=y]) && HAS_DMA [=y] && USB_XHCI_HCD [=y] Selected by [m]: - USB_CDNS_SUPPORT [=m] && USB_SUPPORT [=y] && (USB [=y] || USB_GADGET [=y]) && HAS_DMA [=y] && USB_XHCI_HCD [=y] - USB_BRCMSTB [=m] && USB_SUPPORT [=y] && USB [=y] && (ARCH_BRCMSTB [=y] && PHY_BRCM_USB [=m] || COMPILE_TEST [=y]) && USB_XHCI_HCD [=y] - USB_XHCI_MVEBU [=m] && USB_SUPPORT [=y] && USB [=y] && USB_XHCI_HCD [=y] && HAS_IOMEM [=y] && (ARCH_MVEBU [=y] || COMPILE_TEST [=y]) I read through kconfig-language.rst and experimented a fair bit, but haven't found a working solution. Any advice would be appreciated. Thanks Matthias
