When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
is set to 'm', we encountered an ld.lld error during the build process:
ld.lld: error: undefined symbol: backlight_device_get_by_name
>>> referenced by intel_backlight.c:955
>>> vmlinux.o:(intel_backlight_device_register)
ld.lld: error: undefined symbol: backlight_device_register
>>> referenced by intel_backlight.c:971
>>> vmlinux.o:(intel_backlight_device_register)
ld.lld: error: undefined symbol: backlight_device_unregister
>>> referenced by intel_backlight.c:999
>>> vmlinux.o:(intel_backlight_device_unregister)
This issue occurred because intel_backlight_device_register and
intel_backlight_device_unregister were enclosed within
However, according to Kconfig, CONFIG_DRM_I915 will select
BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
This led to an error, which can be resolved by removing the
conditional statements related to ACPI.
Signed-off-by: Wang Jinchao <[email protected]>
---
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 01b5a8272a27..5003de921bf7 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
+ select BACKLIGHT_CLASS_DEVICE
select INPUT if ACPI
select X86_PLATFORM_DEVICES if ACPI
select ACPI_WMI if ACPI
--
2.40.0
On Sat, 12 Aug 2023, Wang Jinchao <[email protected]> wrote:
> When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
> is set to 'm', we encountered an ld.lld error during the build process:
>
> ld.lld: error: undefined symbol: backlight_device_get_by_name
> >>> referenced by intel_backlight.c:955
> >>> vmlinux.o:(intel_backlight_device_register)
>
> ld.lld: error: undefined symbol: backlight_device_register
> >>> referenced by intel_backlight.c:971
> >>> vmlinux.o:(intel_backlight_device_register)
>
> ld.lld: error: undefined symbol: backlight_device_unregister
> >>> referenced by intel_backlight.c:999
> >>> vmlinux.o:(intel_backlight_device_unregister)
>
> This issue occurred because intel_backlight_device_register and
> intel_backlight_device_unregister were enclosed within
> However, according to Kconfig, CONFIG_DRM_I915 will select
> BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
> This led to an error, which can be resolved by removing the
> conditional statements related to ACPI.
The real fix is to use
depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n
but in order to do that, you need to change a lot of places to depend
on, not select BACKLIGHT_CLASS_DEVICE, because otherwise you end up with
other dependency issues.
BR,
Jani.
>
> Signed-off-by: Wang Jinchao <[email protected]>
> ---
> 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 01b5a8272a27..5003de921bf7 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
> + select BACKLIGHT_CLASS_DEVICE
> select INPUT if ACPI
> select X86_PLATFORM_DEVICES if ACPI
> select ACPI_WMI if ACPI
--
Jani Nikula, Intel Open Source Graphics Center
On Mon, Aug 14, 2023 at 03:13:32PM +0300, Jani Nikula wrote:
> On Mon, 14 Aug 2023, Wang Jinchao <[email protected]> wrote:
> > On Mon, Aug 14, 2023 at 10:26:45AM +0300, Jani Nikula wrote:
> >> On Sat, 12 Aug 2023, Wang Jinchao <[email protected]> wrote:
> >> > When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
> >> > is set to 'm', we encountered an ld.lld error during the build process:
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_get_by_name
> >> > >>> referenced by intel_backlight.c:955
> >> > >>> vmlinux.o:(intel_backlight_device_register)
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_register
> >> > >>> referenced by intel_backlight.c:971
> >> > >>> vmlinux.o:(intel_backlight_device_register)
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_unregister
> >> > >>> referenced by intel_backlight.c:999
> >> > >>> vmlinux.o:(intel_backlight_device_unregister)
> >> >
> >> > This issue occurred because intel_backlight_device_register and
> >> > intel_backlight_device_unregister were enclosed within
> >> > However, according to Kconfig, CONFIG_DRM_I915 will select
> >> > BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
> >> > This led to an error, which can be resolved by removing the
> >> > conditional statements related to ACPI.
> >>
> >> The real fix is to use
> >>
> >> depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n
> > it works.
> >>
> >> but in order to do that, you need to change a lot of places to depend
> > Why, what are the other places?
>
> Generally when you have a mixture of depends on and select on a kconfig
> symbol, you'll eventually end up with dependency problems.
>
Using A to represent DRM_I915 and B to represent BACKLIGHT_CLASS_DEVICE,
as both A and B are tristate options, all the possibilities include:
1. A=n, B=n
2. A=m, B=n
3. A=y, B=n
4. A=n, B=m
5. A=m, B=m
6. A=y, B=m
7. A=n, B=y
8. A=m, B=y
9. A=y, B=y
Among them, only the 6th case (A=y, B=m) would lead to a compilation failure.
Based on your suggestion, I tested the following configuration:
config A
tristate "A Option"
depends on B || B=n
config B
tristate "B Option"
I tested it using menuconfig, and found that the 6th combination (A=y, B=m)
cannot be manually selected.
Specifically, if B=m, A can only be selected as either n or m.
If A=y and B is set to m, A automatically changes to m as well.
I believe there is no issue with the solution you provided.
Is there something that I might have overlooked?
> BR,
> Jani.
>
>
> >> on, not select BACKLIGHT_CLASS_DEVICE, because otherwise you end up with
> > got it.
> >> other dependency issues.
> >>
> >> BR,
> >> Jani.
> >>
> >> >
> >> > Signed-off-by: Wang Jinchao <[email protected]>
> >> > ---
> >> > 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 01b5a8272a27..5003de921bf7 100644
> >> > --- a/drivers/gpu/drm/i915/Kconfig
> >> > +++ b/drivers/gpu/drm/i915/Kconfig
> >> > @@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
> >> > + select BACKLIGHT_CLASS_DEVICE
> >> > select INPUT if ACPI
> >> > select X86_PLATFORM_DEVICES if ACPI
> >> > select ACPI_WMI if ACPI
> >>
> >> --
> >> Jani Nikula, Intel Open Source Graphics Center
>
> --
> Jani Nikula, Intel Open Source Graphics Center
On Mon, Aug 14, 2023 at 10:26:45AM +0300, Jani Nikula wrote:
> On Sat, 12 Aug 2023, Wang Jinchao <[email protected]> wrote:
> > When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
> > is set to 'm', we encountered an ld.lld error during the build process:
> >
> > ld.lld: error: undefined symbol: backlight_device_get_by_name
> > >>> referenced by intel_backlight.c:955
> > >>> vmlinux.o:(intel_backlight_device_register)
> >
> > ld.lld: error: undefined symbol: backlight_device_register
> > >>> referenced by intel_backlight.c:971
> > >>> vmlinux.o:(intel_backlight_device_register)
> >
> > ld.lld: error: undefined symbol: backlight_device_unregister
> > >>> referenced by intel_backlight.c:999
> > >>> vmlinux.o:(intel_backlight_device_unregister)
> >
> > This issue occurred because intel_backlight_device_register and
> > intel_backlight_device_unregister were enclosed within
> > However, according to Kconfig, CONFIG_DRM_I915 will select
> > BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
> > This led to an error, which can be resolved by removing the
> > conditional statements related to ACPI.
>
> The real fix is to use
>
> depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n
it works.
>
> but in order to do that, you need to change a lot of places to depend
Why, what are the other places?
> on, not select BACKLIGHT_CLASS_DEVICE, because otherwise you end up with
got it.
> other dependency issues.
>
> BR,
> Jani.
>
> >
> > Signed-off-by: Wang Jinchao <[email protected]>
> > ---
> > 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 01b5a8272a27..5003de921bf7 100644
> > --- a/drivers/gpu/drm/i915/Kconfig
> > +++ b/drivers/gpu/drm/i915/Kconfig
> > @@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
> > + select BACKLIGHT_CLASS_DEVICE
> > select INPUT if ACPI
> > select X86_PLATFORM_DEVICES if ACPI
> > select ACPI_WMI if ACPI
>
> --
> Jani Nikula, Intel Open Source Graphics Center
On Mon, 14 Aug 2023, Wang Jinchao <[email protected]> wrote:
> On Mon, Aug 14, 2023 at 10:26:45AM +0300, Jani Nikula wrote:
>> On Sat, 12 Aug 2023, Wang Jinchao <[email protected]> wrote:
>> > When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
>> > is set to 'm', we encountered an ld.lld error during the build process:
>> >
>> > ld.lld: error: undefined symbol: backlight_device_get_by_name
>> > >>> referenced by intel_backlight.c:955
>> > >>> vmlinux.o:(intel_backlight_device_register)
>> >
>> > ld.lld: error: undefined symbol: backlight_device_register
>> > >>> referenced by intel_backlight.c:971
>> > >>> vmlinux.o:(intel_backlight_device_register)
>> >
>> > ld.lld: error: undefined symbol: backlight_device_unregister
>> > >>> referenced by intel_backlight.c:999
>> > >>> vmlinux.o:(intel_backlight_device_unregister)
>> >
>> > This issue occurred because intel_backlight_device_register and
>> > intel_backlight_device_unregister were enclosed within
>> > However, according to Kconfig, CONFIG_DRM_I915 will select
>> > BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
>> > This led to an error, which can be resolved by removing the
>> > conditional statements related to ACPI.
>>
>> The real fix is to use
>>
>> depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n
> it works.
>>
>> but in order to do that, you need to change a lot of places to depend
> Why, what are the other places?
Generally when you have a mixture of depends on and select on a kconfig
symbol, you'll eventually end up with dependency problems.
BR,
Jani.
>> on, not select BACKLIGHT_CLASS_DEVICE, because otherwise you end up with
> got it.
>> other dependency issues.
>>
>> BR,
>> Jani.
>>
>> >
>> > Signed-off-by: Wang Jinchao <[email protected]>
>> > ---
>> > 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 01b5a8272a27..5003de921bf7 100644
>> > --- a/drivers/gpu/drm/i915/Kconfig
>> > +++ b/drivers/gpu/drm/i915/Kconfig
>> > @@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
>> > + select BACKLIGHT_CLASS_DEVICE
>> > select INPUT if ACPI
>> > select X86_PLATFORM_DEVICES if ACPI
>> > select ACPI_WMI if ACPI
>>
>> --
>> Jani Nikula, Intel Open Source Graphics Center
--
Jani Nikula, Intel Open Source Graphics Center
On Mon, Aug 14, 2023 at 03:13:32PM +0300, Jani Nikula wrote:
> On Mon, 14 Aug 2023, Wang Jinchao <[email protected]> wrote:
> > On Mon, Aug 14, 2023 at 10:26:45AM +0300, Jani Nikula wrote:
> >> On Sat, 12 Aug 2023, Wang Jinchao <[email protected]> wrote:
> >> > When CONFIG_DRM_I915 is set to 'y' and CONFIG_BACKLIGHT_CLASS_DEVICE
> >> > is set to 'm', we encountered an ld.lld error during the build process:
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_get_by_name
> >> > >>> referenced by intel_backlight.c:955
> >> > >>> vmlinux.o:(intel_backlight_device_register)
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_register
> >> > >>> referenced by intel_backlight.c:971
> >> > >>> vmlinux.o:(intel_backlight_device_register)
> >> >
> >> > ld.lld: error: undefined symbol: backlight_device_unregister
> >> > >>> referenced by intel_backlight.c:999
> >> > >>> vmlinux.o:(intel_backlight_device_unregister)
> >> >
> >> > This issue occurred because intel_backlight_device_register and
> >> > intel_backlight_device_unregister were enclosed within
> >> > However, according to Kconfig, CONFIG_DRM_I915 will select
> >> > BACKLIGHT_CLASS_DEVICE only if ACPI is enabled.
> >> > This led to an error, which can be resolved by removing the
> >> > conditional statements related to ACPI.
> >>
> >> The real fix is to use
> >>
> >> depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n
> > it works.
> >>
> >> but in order to do that, you need to change a lot of places to depend
> > Why, what are the other places?
>
> Generally when you have a mixture of depends on and select on a kconfig
> symbol, you'll eventually end up with dependency problems.
>
> BR,
> Jani.
>
Now that I understand what you said, I will make an effort to correct it.
GEN Makefile
drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on BACKLIGHT_CLASS_DEVICE
drivers/video/backlight/Kconfig:136: symbol BACKLIGHT_CLASS_DEVICE is selected by DRM_FSL_DCU
drivers/gpu/drm/fsl-dcu/Kconfig:2: symbol DRM_FSL_DCU depends on COMMON_CLK
drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
arch/x86/Kconfig:627: symbol X86_INTEL_QUARK depends on X86_PLATFORM_DEVICES
drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected by DRM_I915
For a resolution refer to Documentation/kbuild/kconfig-language.rst
subsection "Kconfig recursive dependency limitations"
>
> >> on, not select BACKLIGHT_CLASS_DEVICE, because otherwise you end up with
> > got it.
> >> other dependency issues.
> >>
> >> BR,
> >> Jani.
> >>
> >> >
> >> > Signed-off-by: Wang Jinchao <[email protected]>
> >> > ---
> >> > 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 01b5a8272a27..5003de921bf7 100644
> >> > --- a/drivers/gpu/drm/i915/Kconfig
> >> > +++ b/drivers/gpu/drm/i915/Kconfig
> >> > @@ -24,7 +24,7 @@ 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 BACKLIGHT_CLASS_DEVICE if ACPI
> >> > + select BACKLIGHT_CLASS_DEVICE
> >> > select INPUT if ACPI
> >> > select X86_PLATFORM_DEVICES if ACPI
> >> > select ACPI_WMI if ACPI
> >>
> >> --
> >> Jani Nikula, Intel Open Source Graphics Center
>
> --
> Jani Nikula, Intel Open Source Graphics Center