Re: [PATCH] nouveau: make backlight support non optional

On Sat, 24 Jul 2021, Arnd Bergmann arnd@kernel.org wrote:

On Sat, Jul 24, 2021 at 4:14 PM Karol Herbst kherbst@redhat.com wrote:

...

we use the MXM_WMI in code. We also have to keep arm in mind and not break stuff there. So I will try to play around with your changes and see how that goes.

Ok, should find any randconfig build failures for arm, arm64 or x86 over the weekend. I also this on linux-next today

ld: drivers/gpu/drm/i915/display/intel_panel.o: in function `intel_backlight_device_register': intel_panel.c:(.text+0x2804): undefined reference to `backlight_device_register' ld: intel_panel.c:(.text+0x284e): undefined reference to `backlight_device_register' ld: drivers/gpu/drm/i915/display/intel_panel.o: in function `intel_backlight_device_unregister': intel_panel.c:(.text+0x28b1): undefined reference to `backlight_device_unregister'

and I added this same thing there to see how it goes:

Last I checked (and it was a while a go) you really had to make all users of BACKLIGHT_CLASS_DEVICE depend not select it, otherwise you end up with recursive dependencies.

BR, Jani.

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig index 87825d36335b..69c6b7aec49e 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
    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

•   select DRM_I915_BACKLIGHT if ACPI
  

•   select INPUT if ACPI
  

•   select ACPI_VIDEO if ACPI
  

•   select ACPI_BUTTON if ACPI
    select SYNC_FILE
    select IOSF_MBI
    select CRC32
  

@@ -64,13 +62,7 @@ config DRM_I915_FORCE_PROBE Use "*" to force probe the driver for all known devices.

config DRM_I915_BACKLIGHT

•   tristate "Control backlight support"
  

•   depends on DRM_I915
  

•   default DRM_I915
  

•   select BACKLIGHT_CLASS_DEVICE
  

•   help
  

•      Say Y here if you want to control the backlight of your display
  

•      (e.g. a laptop panel).
  

•   def_tristate DRM_I915
  
  

config DRM_I915_CAPTURE_ERROR bool "Enable capturing GPU state following a hang"