On Thu, Apr 8, 2021 at 2:50 PM Linus Walleij [off-list ref] wrote:

On Thu, Apr 8, 2021 at 2:01 PM David Hildenbrand [off-list ref] wrote:

quoted

quoted

This is something you could do using a hidden helper symbol like

config DRMA_ASPEED_GFX
        bool "Aspeed display driver"
        select DRM_WANT_CMA

config DRM_WANT_CMA
        bool
        help
           Select this from any driver that benefits from CMA being enabled

config DMA_CMA
        bool "Use CMA helpers for DRM"
        default DRM_WANT_CMA

          Arnd

That's precisely what I had first, with an additional "WANT_CMA" --  but
looking at the number of such existing options (I was able to spot 1 !)

If you do this it probably makes sense to fix a few other drivers
Kconfig in the process. It's not just a problem with your driver.
"my" drivers:

drivers/gpu/drm/mcde/Kconfig
drivers/gpu/drm/pl111/Kconfig
drivers/gpu/drm/tve200/Kconfig

certainly needs this as well, and pretty much anything that is
selecting DRM_KMS_CMA_HELPER or
DRM_GEM_CMA_HELPER "wants" DMA_CMA.

Are there any that don't select either of the helpers and
still want CMA? If not, it would be easy to just add

   default  DRM_KMS_CMA_HELPER || DRM_GEM_CMA_HELPER

and skipt the extra symbol.

        Arnd