Re: [PATCH v1 1/1] serial: 8250_ce4100: Fix CONFIG_SERIAL_8250=n build

[Andy Shevchenko]

On Wed, Jul 16, 2025 at 12:14:23PM +0200, Jiri Slaby wrote:
> On 16. 07. 25, 11:44, Andy Shevchenko wrote:
> > On i386, when
> > 
> >    CONFIG_X86_INTEL_CE=y
> >    # CONFIG_SERIAL_8250 is not set
> > 
> > will try to compile the driver and use the stub simultaneously.
> > This breaks the build. Fix it by making sure that the driver
> > compiles only when CONFIG_SERIAL_8250 is also enabled.

...

> > +ifneq ($(CONFIG_SERIAL_8250),)
> 
> Why not ifdef CONFIG_SERIAL_8250 then?

$ git grep -n '^ifn\?eq .*CONFIG_' | wc -l
427
$ git grep -n '^ifdef CONFIG_' | wc -l
431

Is there a preference in serial drivers?

> Also, what happens if 8250=m and X86_INTEL_CE=y?

So, in such a case if somebody wants to use UART, it will go crazy due to
missed workaround applied. BUT, this is preexisted issue and not related
(directly) to this fix. Perhaps we can combine both with

ifeq ($(CONFIG_SERIAL_8250),y)

and add two Fixes tags.

> >   obj-$(CONFIG_X86_INTEL_CE)		+= 8250_ce4100.o
> > +endif

-- 
With Best Regards,
Andy Shevchenko