[PATCH] drm/exynos: add CONFIG_MMU dependency

[PATCH] drm/exynos: add CONFIG_MMU dependency

[Arnd Bergmann]

Compile-testing this driver on a NOMMU configuration shows a link failure:

drivers/gpu/drm/exynos/exynos_drm_gem.o: In function `exynos_drm_gem_fault':
exynos_drm_gem.c:(.text+0x484): undefined reference to `vmf_insert_mixed'

Add a CONFIG_MMU dependency to ensure we only enable this in configurations
that build correctly.

Many other drm drivers have the same dependency. It would be nice to
make this work in MMU-less configurations, but evidently nobody has
ever needed this so far.

Fixes: 156bdac99061 ("drm/exynos: trigger build of all modules")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/exynos/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 60ce4a8ad9e1..6f7d3b3b3628 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -2,6 +2,7 @@
 config DRM_EXYNOS
 	tristate "DRM Support for Samsung SoC EXYNOS Series"
 	depends on OF && DRM && (ARCH_S3C64XX || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_MULTIPLATFORM || COMPILE_TEST)
+	depends on MMU
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
 	select SND_SOC_HDMI_CODEC if SND_SOC
-- 
2.20.0

Re: [PATCH] drm/exynos: add CONFIG_MMU dependency

[Vladimir Murzin]

On 7/8/19 2:46 PM, Arnd Bergmann wrote:
> Compile-testing this driver on a NOMMU configuration shows a link failure:
> 
> drivers/gpu/drm/exynos/exynos_drm_gem.o: In function `exynos_drm_gem_fault':
> exynos_drm_gem.c:(.text+0x484): undefined reference to `vmf_insert_mixed'
> 
> Add a CONFIG_MMU dependency to ensure we only enable this in configurations
> that build correctly.
> 
> Many other drm drivers have the same dependency. It would be nice to
> make this work in MMU-less configurations, but evidently nobody has
> ever needed this so far.
> 
> Fixes: 156bdac99061 ("drm/exynos: trigger build of all modules")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/gpu/drm/exynos/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
> index 60ce4a8ad9e1..6f7d3b3b3628 100644
> --- a/drivers/gpu/drm/exynos/Kconfig
> +++ b/drivers/gpu/drm/exynos/Kconfig
> @@ -2,6 +2,7 @@
>  config DRM_EXYNOS
>  	tristate "DRM Support for Samsung SoC EXYNOS Series"
>  	depends on OF && DRM && (ARCH_S3C64XX || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_MULTIPLATFORM || COMPILE_TEST)
> +	depends on MMU
>  	select DRM_KMS_HELPER
>  	select VIDEOMODE_HELPERS
>  	select SND_SOC_HDMI_CODEC if SND_SOC
> 

I seen

ERROR: "vmf_insert_mixed" [drivers/gpu/drm/exynos/exynosdrm.ko] undefined!

with older kernels when driver was build as a module, so FWIW

Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>

Cheers
Vladimir