Created attachment 293225 [details]
kernel config file and the build output

Attachment (reproduce.tar.gz) content:
 - sample.config: Config file to reproduce the bug.
 - build_out.txt: Output of Kbuild including the error messages.

When BCMA_DRIVER_PCI_HOSTMODE is enabled and BCMA_DRIVER_PCI_HOSTMODE is
disabled, it results in the following Kbuild warning:

WARNING: unmet direct dependencies detected for BCMA_DRIVER_PCI_HOSTMODE
  Depends on [n]: MIPS [=y] && BCMA_DRIVER_PCI [=n] && PCI_DRIVERS_LEGACY [=y] && BCMA [=y]=y
  Selected by [y]:
  - BCM47XX_BCMA [=y] && BCM47XX [=y] && PCI [=y]

Building the kernel fails due to this unmet direct dependency issue as follows:

[...]
drivers/bcma/driver_pci_host.c: In function 'bcma_get_cfgspace_addr':
drivers/bcma/driver_pci_host.c:67:20: error: implicit declaration of function 'bcma_pcie_read'; did you mean 'raw_pci_read'? [-Werror=implicit-function-declaration]
   67 |  if (dev >= 2 || !(bcma_pcie_read(pc, BCMA_CORE_PCI_DLLP_LSREG)
      |                    ^~~~~~~~~~~~~~
      |                    raw_pci_read
[...]
cc1: some warnings being treated as errors
scripts/Makefile.build:265: recipe for target 'drivers/bcma/driver_pci_host.o' failed
make[2]: *** [drivers/bcma/driver_pci_host.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[...]

Steps to reproduce the bug for v5.4.4:
  1. wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
  2. chmod +x ~/bin/make.cross
  3. tar -xvf reproduce.tar.gz # sample.config and build_out.txt
  4. cp sample.config path/to/linux-source-v5.4.4/.config
  5. cd path/to/linux-source-v5.4.4/
  6. ~/bin/make.cross ARCH=mips clean
  7. ~/bin/make.cross ARCH=mips olddefconfig # unmet direct dependency warning
  8. ~/bin/make.cross ARCH=mips # should have a build error

The output for the steps [6-8] can be found in build_out.txt.

The bug is reproducible for v5.10-rc1 as well with the same steps.

Kernel successfully builds when the unmet direct dependencies are resolved
by enabling them in the configuration. Depending on instead of selecting
the symbols, or selecting the dependencies of the selected symbols as well
should fix the bug.

Thanks,
Necip