On Wed, 27 Oct 2021, Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > The i915 driver can use the backlight subsystem as an option, and usually > selects it when CONFIG_ACPI is set. However it is possible to configure > a kernel with modular backlight classdev support and a built-in i915 > driver, which leads to a linker error: > > drivers/gpu/drm/i915/display/intel_panel.o: In function `intel_backlight_device_register': > intel_panel.c:(.text+0x2f58): undefined reference to `backlight_device_register' > drivers/gpu/drm/i915/display/intel_panel.o: In function `intel_backlight_device_unregister': > intel_panel.c:(.text+0x2fe4): undefined reference to `backlight_device_unregister' > > Change i915 to just 'depends on' for both BACKLIGHT_CLASS_DEVICE > and ACPI_VIDEO, which avoids a lot of the problems. > > Link: https://lore.kernel.org/all/20200108140227.3976563-1-arnd@xxxxxxxx/ > Link: https://lore.kernel.org/all/20200417155553.675905-1-arnd@xxxxxxxx/ > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > This change depends on cleaning up drivers/video/fbdev to no longer > 'select' I2C and BACKLIGHT_CLASS_DEVICE, otherwise it causes > dependency loops. > --- > drivers/gpu/drm/i915/Kconfig | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig > index 84b6fc70cbf5..f427e6d50d9b 100644 > --- a/drivers/gpu/drm/i915/Kconfig > +++ b/drivers/gpu/drm/i915/Kconfig > @@ -3,6 +3,8 @@ config DRM_I915 > tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics" > depends on DRM > depends on X86 && PCI > + depends on ACPI_VIDEO || !ACPI > + depends on BACKLIGHT_CLASS_DEVICE || !BACKLIGHT_CLASS_DEVICE > select INTEL_GTT > select INTERVAL_TREE > # we need shmfs for the swappable backing store, and in particular > @@ -16,10 +18,6 @@ config DRM_I915 > select IRQ_WORK > # i915 depends on ACPI_VIDEO when ACPI is enabled > # but for select to work, need to select ACPI_VIDEO's dependencies, ick The comment needs updating as well. Other than that, Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx> on the series. > - select BACKLIGHT_CLASS_DEVICE if ACPI > - select INPUT if ACPI > - select ACPI_VIDEO if ACPI > - select ACPI_BUTTON if ACPI > select SYNC_FILE > select IOSF_MBI > select CRC32 -- Jani Nikula, Intel Open Source Graphics Center
