On 30.03.17, Jani Nikula wrote: > On Wed, 29 Mar 2017, Tobias Regnery <tobias.regnery@xxxxxxxxx> wrote: > > With CONFIG_ACPI=n and CONFIG_BACKLIGHT_CLASS_DEVICE=n we see the following > > link error in the i915 driver: > > > > drivers/built-in.o: In function 'intel_backlight_device_register': > > (.text+0x2a921d): undefined reference to 'backlight_device_register' > > > > Fix this by removing the condition on ACPI from the appropriate select > > statement. > > The right fix for the build problem is to add empty stub functions for > BACKLIGHT_CLASS_DEVICE=n in include/linux/backlight.h. I'm frankly > surprised nobody's done that yet. Thanks for the advice, I will try to come up with a patch. -- Tobias > > It's another question whether we should support and select backlight for > ACPI=n, and yet another question whether we should support ACPI=n. > > Also, selecting BACKLIGHT_CLASS_DEVICE is fundamentally broken, but > people aren't interested [1]. > > > BR, > Jani. > > [1] http://mid.mail-archive.com/1413580403-16225-1-git-send-email-jani.nikula@xxxxxxxxx > > > > > Signed-off-by: Tobias Regnery <tobias.regnery@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/Kconfig | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig > > index a5cd5dacf055..532df4bb9283 100644 > > --- a/drivers/gpu/drm/i915/Kconfig > > +++ b/drivers/gpu/drm/i915/Kconfig > > @@ -15,7 +15,7 @@ config DRM_I915 > > # i915 depends on ACPI_VIDEO when ACPI is enabled > > # but for select to work, need to select ACPI_VIDEO's dependencies, ick > > select BACKLIGHT_LCD_SUPPORT if ACPI > > - select BACKLIGHT_CLASS_DEVICE if ACPI > > + select BACKLIGHT_CLASS_DEVICE > > select INPUT if ACPI > > select ACPI_VIDEO if ACPI > > select ACPI_BUTTON if ACPI > > -- > Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
