On 01/10/2017 04:16 AM, Arnd Bergmann wrote:

If CONFIG_INPUT=m, we get a build error for the rmi4-f03 driver,
added in linux-4.10:

drivers/input/built-in.o: In function `rmi_f03_attention':
rmi_f03.c:(.text+0xcfe0): undefined reference to `serio_interrupt'
rmi_f03.c:(.text+0xd055): undefined reference to `serio_interrupt'
drivers/input/built-in.o: In function `rmi_f03_remove':
rmi_f03.c:(.text+0xd115): undefined reference to `serio_unregister_port'
drivers/input/built-in.o: In function `rmi_f03_probe':
rmi_f03.c:(.text+0xd209): undefined reference to `__serio_register_port'

If we make the driver itself a 'tristate' instead of 'bool' symbol,
Kconfig ensures that it can only be a loadable module in this case,
which avoids the problem.

Unfortunately, the RMI4 driver does not support building the function 
drivers as modules. If F03 is built as a module it will not be loaded by 
the core. If we want f03 to be part of a module then rmi_core needs to 
be built as a module. We should remove the module macros currently in 
rmi_f03.c.

I was able to get a similar build error by setting CONFIG_RMI_CORE=y and 
CONFIG_SERIO=m. Was CONFIG_RMI_CORE=y set when you encountered this 
error? If so I think we should figure out a way to have Kconfig set 
CONFIG_RMI_CORE=m if serio is built as a module.

Andrew