DRM_STM breaks fbdev mmap on ARCH_MULTIPLATFORM

[Benjamin Gaignard]

2017-07-10 12:53 GMT+02:00 Noralf Trønnes <noralf at tronnes.org>:
> Hi
>
> DRM_STM is 'default y' on ARCH_MULTIPLATFORM and it selects
> FB_PROVIDE_GET_FB_UNMAPPED_AREA. This breaks fbdev mmap for me on
> Raspberry Pi. mmap returns -ENOMEM.
>
> Disabling DRM_STM gives me working mmap.
>
> Noralf.
>
>
> config DRM_STM
>     tristate "DRM Support for STMicroelectronics SoC Series"
>     depends on DRM && (ARCH_STM32 || ARCH_MULTIPLATFORM)
>     select DRM_KMS_HELPER
>     select DRM_GEM_CMA_HELPER
>     select DRM_KMS_CMA_HELPER
>     select DRM_PANEL
>     select VIDEOMODE_HELPERS
>     select FB_PROVIDE_GET_FB_UNMAPPED_AREA

I think to two solutions:
- add "if !MMU" after FB_PROVIDE_GET_FB_UNMAPPED_AREA in this Kconfig
but other drivers could do the same.
- add !MMU when FB_PROVIDE_GET_FB_UNMAPPED_AREA is used in fbmen.c

>     default y
>
>     help
>       Enable support for the on-chip display controller on
>       STMicroelectronics STM32 MCUs.
>       To compile this driver as a module, choose M here: the module
>       will be called stm-drm.
>
>
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