Nouveau - May 2020 - [PATCH 2/2] nouveau: fix dependencies for DEVICE_PRIVATE

CONFIG_DEVICE_PRIVATE cannot be selected in configurations
without ZONE_DEVICE:

WARNING: unmet direct dependencies detected for DEVICE_PRIVATE
  Depends on [n]: ZONE_DEVICE [=n]
  Selected by [y]:
  - DRM_NOUVEAU_SVM [=y] && HAS_IOMEM [=y] && DRM_NOUVEAU [=y]
&& MMU [=y] && STAGING [=y]
kernel/resource.c:1653:28: error: use of undeclared identifier
'PA_SECTION_SHIFT'
        size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
                                  ^
kernel/resource.c:1654:48: error: use of undeclared identifier
'MAX_PHYSMEM_BITS'

Add a dependency for Nouveau to avoid broken randconfig builds.

Fixes: d2c63df2242e ("mm/hmm: make CONFIG_DEVICE_PRIVATE into a
select")
Signed-off-by: Arnd Bergmann <arnd at arndb.de>
---
 drivers/gpu/drm/nouveau/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/nouveau/Kconfig b/drivers/gpu/drm/nouveau/Kconfig
index af5793f3e7c2..996ec5475908 100644
--- a/drivers/gpu/drm/nouveau/Kconfig
+++ b/drivers/gpu/drm/nouveau/Kconfig
@@ -87,6 +87,7 @@ config DRM_NOUVEAU_BACKLIGHT
 config DRM_NOUVEAU_SVM
 	bool "(EXPERIMENTAL) Enable SVM (Shared Virtual Memory) support"
 	depends on DRM_NOUVEAU
+	depends on ZONE_DEVICE
 	depends on MMU
 	depends on STAGING
 	select DEVICE_PRIVATE
-- 
2.26.0

On Fri, May 08, 2020 at 04:40:09PM +0200, Arnd Bergmann
wrote:
> CONFIG_DEVICE_PRIVATE cannot be selected in configurations
> without ZONE_DEVICE:
It is kind of unfortunate to lift dependencies from DEVICE_PRIVATE
into the users, is this really how kconfig is supposed to work or is
something else wrong here?

Jason

On Fri, May 8, 2020 at 5:00 PM Jason Gunthorpe <jgg at mellanox.com>
wrote:
>
> On Fri, May 08, 2020 at 04:40:09PM +0200, Arnd Bergmann wrote:
> > CONFIG_DEVICE_PRIVATE cannot be selected in configurations
> > without ZONE_DEVICE:
>
> It is kind of unfortunate to lift dependencies from DEVICE_PRIVATE
> into the users, is this really how kconfig is supposed to work or is
> something else wrong here?
Usually the problem is trying to use 'select' for something that can
be done with 'depends on'. I have actually no idea what
CONFIG_DEVICE_PRIVATE does, as it lacks a help text
and is a rather generic term.

Would it be possible to decouple DEVICE_PRIVATE from ZONE_DEVICE?
It sounds like the first is related to the device model, while
the second is for memory management, so maybe the dependency
is not necessary.

       Arnd

On 5/8/20 7:40 AM, Arnd Bergmann wrote:
> CONFIG_DEVICE_PRIVATE cannot be selected in configurations
> without ZONE_DEVICE:
> 
> WARNING: unmet direct dependencies detected for DEVICE_PRIVATE
>   Depends on [n]: ZONE_DEVICE [=n]
>   Selected by [y]:
>   - DRM_NOUVEAU_SVM [=y] && HAS_IOMEM [=y] && DRM_NOUVEAU
[=y] && MMU [=y] && STAGING [=y]
> kernel/resource.c:1653:28: error: use of undeclared identifier
'PA_SECTION_SHIFT'
>         size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
>                                   ^
> kernel/resource.c:1654:48: error: use of undeclared identifier
'MAX_PHYSMEM_BITS'
> 
> Add a dependency for Nouveau to avoid broken randconfig builds.
> 
> Fixes: d2c63df2242e ("mm/hmm: make CONFIG_DEVICE_PRIVATE into a
select")
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>
Acked-by: Randy Dunlap <rdunlap at infradead.org> # build-tested

Thanks.
> ---
>  drivers/gpu/drm/nouveau/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/Kconfig
b/drivers/gpu/drm/nouveau/Kconfig
> index af5793f3e7c2..996ec5475908 100644
> --- a/drivers/gpu/drm/nouveau/Kconfig
> +++ b/drivers/gpu/drm/nouveau/Kconfig
> @@ -87,6 +87,7 @@ config DRM_NOUVEAU_BACKLIGHT
>  config DRM_NOUVEAU_SVM
>  	bool "(EXPERIMENTAL) Enable SVM (Shared Virtual Memory)
support"
>  	depends on DRM_NOUVEAU
> +	depends on ZONE_DEVICE
>  	depends on MMU
>  	depends on STAGING
>  	select DEVICE_PRIVATE
> 

-- 
~Randy

On Fri, May 08, 2020 at 04:40:09PM +0200, Arnd Bergmann
wrote:
> CONFIG_DEVICE_PRIVATE cannot be selected in configurations
> without ZONE_DEVICE:
> 
> WARNING: unmet direct dependencies detected for DEVICE_PRIVATE
>   Depends on [n]: ZONE_DEVICE [=n]
>   Selected by [y]:
>   - DRM_NOUVEAU_SVM [=y] && HAS_IOMEM [=y] && DRM_NOUVEAU
[=y] && MMU [=y] && STAGING [=y]
> kernel/resource.c:1653:28: error: use of undeclared identifier
'PA_SECTION_SHIFT'
>         size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
>                                   ^
> kernel/resource.c:1654:48: error: use of undeclared identifier
'MAX_PHYSMEM_BITS'
> 
> Add a dependency for Nouveau to avoid broken randconfig builds.
> 
> Fixes: d2c63df2242e ("mm/hmm: make CONFIG_DEVICE_PRIVATE into a
> select")
I've reverted the patch this fixes, it seems more trouble than it is
worth.

Thanks,
Jason