| Message ID | 20180223131112.715992-1-arnd@arndb.de |
|---|---|
| State | Accepted |
| Commit | 3156b53c2e2fadafa1a16412a8791b38f94b5bdc |
| Headers | show |
| Series | drm/sun4i: link in front-end code if needed | expand |
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 -- Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
On Mon, Feb 26, 2018 at 6:53 PM, Maxime Ripard <maxime.ripard@bootlin.com> wrote: > 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 This doesn't solve the issue at hand, which is sun4i-drv (CONFIG_DRM_SUN4I) requires something in sun4i-backend (CONFIG_DRM_SUN4I_BACKEND), and if sun4i-drv is built-in, then anything it uses must also be built-in. ChenYu
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 obj-$(CONFIG_DRM_SUN4I_HDMI) += sun4i-drm-hdmi.o obj-$(CONFIG_DRM_SUN8I_MIXER) += sun8i-mixer.o
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(-)