[PATCH v2 1/1] serial: 8250_ce4100: Fix CONFIG_SERIAL_8250=n build

[PATCH v2 1/1] serial: 8250_ce4100: Fix CONFIG_SERIAL_8250=n build

[Andy Shevchenko]

On i386, when

  CONFIG_X86_INTEL_CE=y
  # CONFIG_SERIAL_8250 is not set

it 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.

On top of that ensure that CONFIG_SERIAL_8250 is actually set to 'y'
and not 'm' as the later makes no sense for this platform. The hook
may only be applied during early boot.

Fixes: acc902de05b2 ("serial: 8250: Move CE4100 quirks to a module under 8250 driver")
Fixes: 5ec6960f6f0c ("ce4100: Add errata fixes for UART on CE4100")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/r/cdf4ee46-7bf8-4379-9245-fed9db72e7e8@infradead.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---

v2: made the fix more readable (Jiri)

 drivers/tty/serial/8250/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index e61dc3f4ca50..513a0941c284 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -24,7 +24,9 @@ obj-$(CONFIG_SERIAL_8250_ASPEED_VUART)	+= 8250_aspeed_vuart.o
 obj-$(CONFIG_SERIAL_8250_BCM2835AUX)	+= 8250_bcm2835aux.o
 obj-$(CONFIG_SERIAL_8250_BCM7271)	+= 8250_bcm7271.o
 obj-$(CONFIG_SERIAL_8250_BOCA)		+= 8250_boca.o
+ifeq ($(CONFIG_SERIAL_8250),y)
 obj-$(CONFIG_X86_INTEL_CE)		+= 8250_ce4100.o
+endif
 obj-$(CONFIG_SERIAL_8250_DFL)		+= 8250_dfl.o
 obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.o
 obj-$(CONFIG_SERIAL_8250_EM)		+= 8250_em.o
-- 
2.47.2

Re: [PATCH v2 1/1] serial: 8250_ce4100: Fix CONFIG_SERIAL_8250=n build

[Randy Dunlap]

On 7/16/25 7:23 AM, Andy Shevchenko wrote:
> On i386, when
> 
>   CONFIG_X86_INTEL_CE=y
>   # CONFIG_SERIAL_8250 is not set
> 
> it 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.
> 
> On top of that ensure that CONFIG_SERIAL_8250 is actually set to 'y'
> and not 'm' as the later makes no sense for this platform. The hook
> may only be applied during early boot.
> 
> Fixes: acc902de05b2 ("serial: 8250: Move CE4100 quirks to a module under 8250 driver")
> Fixes: 5ec6960f6f0c ("ce4100: Add errata fixes for UART on CE4100")
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Closes: https://lore.kernel.org/r/cdf4ee46-7bf8-4379-9245-fed9db72e7e8@infradead.org
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

This solution works but it seems quite hidden to me. I would rather see
a Kconfig solution, like Jiri mentioned.

Anyway,
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>


Thanks.

> ---
> 
> v2: made the fix more readable (Jiri)
> 
>  drivers/tty/serial/8250/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
> index e61dc3f4ca50..513a0941c284 100644
> --- a/drivers/tty/serial/8250/Makefile
> +++ b/drivers/tty/serial/8250/Makefile
> @@ -24,7 +24,9 @@ obj-$(CONFIG_SERIAL_8250_ASPEED_VUART)	+= 8250_aspeed_vuart.o
>  obj-$(CONFIG_SERIAL_8250_BCM2835AUX)	+= 8250_bcm2835aux.o
>  obj-$(CONFIG_SERIAL_8250_BCM7271)	+= 8250_bcm7271.o
>  obj-$(CONFIG_SERIAL_8250_BOCA)		+= 8250_boca.o
> +ifeq ($(CONFIG_SERIAL_8250),y)
>  obj-$(CONFIG_X86_INTEL_CE)		+= 8250_ce4100.o
> +endif
>  obj-$(CONFIG_SERIAL_8250_DFL)		+= 8250_dfl.o
>  obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.o
>  obj-$(CONFIG_SERIAL_8250_EM)		+= 8250_em.o

-- 
~Randy