Messages in this thread | | | Date | Tue, 19 Jul 2022 04:54:03 +0000 | From | Tzung-Bi Shih <> | Subject | Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning |
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On Mon, Jul 18, 2022 at 06:28:22AM -0700, Guenter Roeck wrote: > On Mon, Jul 18, 2022 at 3:51 AM Tzung-Bi Shih <tzungbi@kernel.org> wrote: > > > > drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning > > when using the randconfig in [1]: > > >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm' > > > > The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set. > > Reproduce: > > - mkdir build_dir > > - wget [1] -O build_dir/.config > > - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \ > > O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/ > > > > Fix the warning by using __maybe_unused. Also use IS_ENABLED() because > > CROS_EC is a tristate. > > Is that sufficient ? What happens if CROS_KBD_LED_BACKLIGHT=y and > CROS_EC=m ? I suspect you might need IS_REACHABLE() instead of > IS_ENABLED().
For current code, it's impossible to set CROS_KBD_LED_BACKLIGHT=y and CROS_EC=m without setting ACPI=y. Given that the dependencies: CHROME_PLATFORMS [=y] && LEDS_CLASS [=y] && (ACPI [=n] || CROS_EC [=m]).
$ ./scripts/kconfig/merge_config.sh -n <(cat <<EOF CONFIG_MODULES=y
CONFIG_NEW_LEDS=y CONFIG_LEDS_CLASS=y
CONFIG_CHROME_PLATFORMS=y CONFIG_CROS_EC=m CONFIG_CROS_KBD_LED_BACKLIGHT=y EOF ) [...] Value requested for CONFIG_CROS_KBD_LED_BACKLIGHT not in final .config Requested value: CONFIG_CROS_KBD_LED_BACKLIGHT=y Actual value: CONFIG_CROS_KBD_LED_BACKLIGHT=m
However, when ACPI=y, `keyboard_led_drvdata_ec_pwm` is unused. Instead, it uses `keyboard_led_drvdata_acpi` for current code.
I guess IS_ENABLED() is sufficient. Does it make sense?
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