On Tue, 2 Dec 2008 20:05:45 +0000 Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote: > > > +#ifdef CONFIG_ACPI > > > + if (acpi_video_backlight_support()) > > > + return 0; > > > +#endif > > > > Do we need the ifdefs here? It looks like include/linux/acpi.h tries > > to provide a suitable 0-returning stub? > > They're protected by #ifdef CONFIG_ACPI_VIDEO, but it looks like acpi.h > is empty if CONFIG_ACPI isn't set? No, acpi.h has a _few_ ACPI=n stubs: : static inline int early_acpi_boot_init(void) : { : return 0; : } : static inline int acpi_boot_init(void) : { : return 0; : } : : static inline int acpi_boot_table_init(void) : { : return 0; : } : : static inline int acpi_mps_check(void) : { : return 0; : } : : static inline int acpi_check_resource_conflict(struct resource *res) : { : return 0; : } : : static inline int acpi_check_region(resource_size_t start, resource_size_t n, : const char *name) : { : return 0; : } : : static inline int acpi_check_mem_region(resource_size_t start, : resource_size_t n, const char *name) : { : return 0; : } So it seems that acpi_video_backlight_support() should be added to this list. Except it already has a stub, in the wrong place. This whole block: : #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) : : extern long acpi_video_get_capabilities(acpi_handle graphics_dev_handle); : extern long acpi_is_video_device(struct acpi_device *device); : extern int acpi_video_backlight_support(void); : extern int acpi_video_display_switch_support(void); : : #else : : static inline long acpi_video_get_capabilities(acpi_handle graphics_dev_handle) : { : return 0; : } : : static inline long acpi_is_video_device(struct acpi_device *device) : { : return 0; : } : : static inline int acpi_video_backlight_support(void) : { : return 0; : } : : static inline int acpi_video_display_switch_support(void) : { : return 0; : } : : #endif /* defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) */ : needs to be moved outside the `#ifdef CONFIG_ACPI' altogether. Then you can drop the ifdef. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html