Nouveau - May 2025 - [PATCH v2 0/3] rust: select AUXILIARY_BUS instead of depending on it

I noticed this after trying to understand why my minimal Nova defconfig
was not selecting NOVA_CORE anymore and why I couldn't even find it in
menuconfig.

CONFIG_AUXILIARY_BUS cannot be enabled directly and must be selected by
another module. Options that depend on it thus cannot be enabled unless
a different module selecting AUXILIARY_BUS is also enabled.

All non-Rust modules using CONFIG_AUXILIARY_BUS select it, so it should
make sense for the Rust ones to use that scheme as well.

Btw Danilo, since the fixed patches are not in mainline yet, please feel
free to just squash these fixes into the original patches if you think
it makes more sense.

Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
Changes in v2:
- Added missing Fixes: tags.
- Collected Reviewed-by: tag.
- Link to v1: https://lore.kernel.org/r/20250515-aux_bus-v1-0-1781b54424e4 at
nvidia.com

---
Alexandre Courbot (3):
      samples: rust: select AUXILIARY_BUS instead of depending on it
      gpu: nova-core: select AUXILIARY_BUS instead of depending on it
      gpu: drm: nova: select AUXILIARY_BUS instead of depending on it

 drivers/gpu/drm/nova/Kconfig  | 2 +-
 drivers/gpu/nova-core/Kconfig | 2 +-
 samples/rust/Kconfig          | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)
---
base-commit: 61479ae38cb7bf6083de302598b7d491ec54168a
change-id: 20250515-aux_bus-c9da900b7c3f

Best regards,
-- 
Alexandre Courbot <acourbot at nvidia.com>

CONFIG_AUXILIARY_BUS cannot be enabled explicitly, and unless we select
it we have no way to include it (and thus to enable the auxiliary driver
sample) unless a driver happens to do it for us.

Fixes: 96609a1969f4 ("samples: rust: add Rust auxiliary driver
sample")
Reviewed-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 samples/rust/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index
43cb72d72631bb2d6e06185e1d88778edff6ee13..b1006ab4bc3c341ef8e25c9b8e865ccf23983a6e
100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -84,8 +84,8 @@ config SAMPLE_RUST_DRIVER_FAUX
 
 config SAMPLE_RUST_DRIVER_AUXILIARY
 	tristate "Auxiliary Driver"
-	depends on AUXILIARY_BUS
 	depends on PCI
+	select AUXILIARY_BUS
 	help
 	  This option builds the Rust auxiliary driver sample.
 

-- 
2.49.0

CONFIG_AUXILIARY_BUS cannot be enabled explicitly, and unless we select
it we have no way to include it (and thus to enable NOVA_CORE) unless
another driver happens to do it for us.

Fixes: e041d81a0377 ("gpu: nova-core: register auxiliary device for
nova-drm")
Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 drivers/gpu/nova-core/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/Kconfig b/drivers/gpu/nova-core/Kconfig
index
67f99b6a023a5706bc809de18f9142938d1d0cd8..8726d80d6ba4013d84d0e6194ccaa9b41a6e4af1
100644
--- a/drivers/gpu/nova-core/Kconfig
+++ b/drivers/gpu/nova-core/Kconfig
@@ -1,9 +1,9 @@
 config NOVA_CORE
 	tristate "Nova Core GPU driver"
-	depends on AUXILIARY_BUS
 	depends on PCI
 	depends on RUST
 	depends on RUST_FW_LOADER_ABSTRACTIONS
+	select AUXILIARY_BUS
 	default n
 	help
 	  Choose this if you want to build the Nova Core driver for Nvidia

-- 
2.49.0

CONFIG_AUXILIARY_BUS cannot be enabled explicitly, and unless we select
it we have no way to include it (and thus to enable NOVA_DRM) unless
another driver happens to do it for us.

Fixes: cdeaeb9dd762 ("drm: nova-drm: add initial driver skeleton")
Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 drivers/gpu/drm/nova/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nova/Kconfig b/drivers/gpu/drm/nova/Kconfig
index
123e96788484ad05a77a5827742c0c88255b1f2f..cca6a3fea879b81c38dd7124942cf2aa09874efa
100644
--- a/drivers/gpu/drm/nova/Kconfig
+++ b/drivers/gpu/drm/nova/Kconfig
@@ -1,9 +1,9 @@
 config DRM_NOVA
 	tristate "Nova DRM driver"
-	depends on AUXILIARY_BUS
 	depends on DRM=y
 	depends on PCI
 	depends on RUST
+	select AUXILIARY_BUS
 	default n
 	help
 	  Choose this if you want to build the Nova DRM driver for Nvidia

-- 
2.49.0

On Thu, May 15, 2025 at 05:23:17PM +0900, Alexandre Courbot
wrote:
> I noticed this after trying to understand why my minimal Nova defconfig
> was not selecting NOVA_CORE anymore and why I couldn't even find it in
> menuconfig.
> 
> CONFIG_AUXILIARY_BUS cannot be enabled directly and must be selected by
> another module. Options that depend on it thus cannot be enabled unless
> a different module selecting AUXILIARY_BUS is also enabled.
> 
> All non-Rust modules using CONFIG_AUXILIARY_BUS select it, so it should
> make sense for the Rust ones to use that scheme as well.
Applied to nova-next, thanks!