On Mon, Feb 26, 2018 at 10:31:51AM +0100, Arnd Bergmann wrote:
On Mon, Feb 26, 2018 at 10:21 AM, Maxime Ripard maxime.ripard@bootlin.com wrote:
Hi,
On Fri, Feb 23, 2018 at 02:06:52PM +0100, Arnd Bergmann wrote:
When the base sun4i DRM driver is built-in but the back-end is a loadable module, we run into a link error:
drivers/gpu/drm/sun4i/sun4i_drv.o: In function `sun4i_drv_probe': sun4i_drv.c:(.text+0x60c): undefined reference to `sun4i_frontend_of_table'
The dependency is a bit tricky, the best workaround I have come up with is to use a Makefile hack to to interpret both CONFIG_DRM_SUN4I_BACKEND=m and CONFIG_DRM_SUN4I_BACKEND=y as a directive to build the front-end the same way as the main module.
Fixes: dd0421f47505 ("drm/sun4i: Add a driver for the display frontend") Signed-off-by: Arnd Bergmann arnd@arndb.de
drivers/gpu/drm/sun4i/Makefile | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile index 582607c0c488..db14e023256b 100644 --- a/drivers/gpu/drm/sun4i/Makefile +++ b/drivers/gpu/drm/sun4i/Makefile @@ -25,6 +25,9 @@ obj-$(CONFIG_DRM_SUN4I) += sun4i-tcon.o obj-$(CONFIG_DRM_SUN4I) += sun4i_tv.o obj-$(CONFIG_DRM_SUN4I) += sun6i_drc.o
-obj-$(CONFIG_DRM_SUN4I_BACKEND) += sun4i-backend.o sun4i-frontend.o +obj-$(CONFIG_DRM_SUN4I_BACKEND) += sun4i-backend.o +ifdef CONFIG_DRM_SUN4I_BACKEND +obj-$(CONFIG_DRM_SUN4I) += sun4i-frontend.o +endif
Can we just create a Kconfig symbol, selected by DRM_SUN4I_BACKEND, and we would export the symbol?
Yes, I think that would work just as well. Something like
config DRM_SUN4I_FRONTEND tristate default DRM_SUN4I if CONFIG_DRM_SUN4I_BACKEND != n
should do the trick.
I had more something like this in mind: https://pastebin.com/raw/XydvzAtz
Maxime