[PATCH] drm: select DRM_KMS_HELPER from DRM_GEM_SHMEM_HELPER

[Arnd Bergmann <arnd@kernel.org>]

From: Arnd Bergmann <arnd@arndb.de>

In the combination of DRM_KMS_HELPER=m, DRM_GEM_SHMEM_HELPER=y, DRM_FBDEV_EMULATION=y,
The shmem code fails to link against the KMS helpers:

x86_64-linux-ld: vmlinux.o: in function `drm_fbdev_shmem_driver_fbdev_probe':
(.text+0xeec601): undefined reference to `drm_fb_helper_alloc_info'
x86_64-linux-ld: (.text+0xeec633): undefined reference to `drm_fb_helper_fill_info'
x86_64-linux-ld: vmlinux.o: in function `drm_fbdev_shmem_get_page':
drm_fbdev_shmem.c:(.text+0xeec7d2): undefined reference to `drm_gem_fb_get_obj'
x86_64-linux-ld: vmlinux.o: in function `drm_fbdev_shmem_fb_mmap':
drm_fbdev_shmem.c:(.text+0xeec9f6): undefined reference to `drm_gem_fb_get_obj'
x86_64-linux-ld: vmlinux.o: in function `drm_fbdev_shmem_defio_imageblit':
(.rodata+0x5b2288): undefined reference to `drm_fb_helper_check_var'
x86_64-linux-ld: (.rodata+0x5b2290): undefined reference to `drm_fb_helper_set_par'

This can happen for a number of device drivers that select DRM_GEM_SHMEM_HELPER
without also selecting DRM_KMS_HELPER. To work around this, add another select
that forces DRM_KMS_HELPER to be built-in rather than a loadable module, but
only if FBDEV emulation is also enabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0fe99d440bfa..a8d2dffbc82f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -311,6 +311,7 @@ config DRM_GEM_SHMEM_HELPER
 	depends on DRM && MMU
 	select FB_CORE if DRM_FBDEV_EMULATION
 	select FB_SYSMEM_HELPERS_DEFERRED if DRM_FBDEV_EMULATION
+	select DRM_KMS_HELPER if DRM_FBDEV_EMULATION
 	help
 	  Choose this if you need the GEM shmem helper functions
 
-- 
2.39.5