From mboxrd@z Thu Jan 1 00:00:00 1970 From: wens@csie.org (Chen-Yu Tsai) Date: Mon, 9 Jul 2018 17:17:35 +0800 Subject: [PATCH] drm/sun4i: fix build failure with CONFIG_DRM_SUN8I_MIXER=m In-Reply-To: <20180709091524.sfamfdmbmwclmegj@flea> References: <20180706124628.3192421-1-arnd@arndb.de> <20180709080724.3ekqb45fsjubvhcm@flea> <20180709091524.sfamfdmbmwclmegj@flea> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jul 9, 2018 at 5:15 PM, Maxime Ripard wrote: > On Mon, Jul 09, 2018 at 04:58:48PM +0800, Chen-Yu Tsai wrote: >> On Mon, Jul 9, 2018 at 4:07 PM, Maxime Ripard wrote: >> > On Fri, Jul 06, 2018 at 02:45:53PM +0200, Arnd Bergmann wrote: >> >> Having DRM_SUN4I built-in but DRM_SUN8I_MIXER as a loadable module results in >> >> a link error, as we try to access a symbol from the sun8i_tcon_top.ko module: >> >> >> >> ERROR: "sun8i_tcon_top_of_table" [drivers/gpu/drm/sun4i/sun8i-drm-hdmi.ko] undefined! >> >> ERROR: "sun8i_tcon_top_of_table" [drivers/gpu/drm/sun4i/sun4i-drm.ko] undefined! >> >> >> >> This solves the problem by making DRM_SUN8I_MIXER a 'bool' symbol, building >> >> the sun8i_tcon_top module the same way as the core sun4i-drm module whenever >> >> DRM_SUN8I_MIXER is enabled, or not building it at all otherwise. >> >> >> >> Alternatively, we could always build sun8i_tcon_top.ko along with sun4-drm.ko >> >> and detach it from the mixer module, I could not tell which way is more >> >> appropriate here. >> > >> > If that's easily doable, then yeah, that would be the preferred option >> > I guess. Jernej? Chen-Yu? Any opinion on this? >> >> Yeah, that definitely works for me. Having TCON TOP being part of the core >> sun4i-drm makes more sense. The TCON code will likely call into it later on >> when Jernej adds the encoder muxing code. >> >> I wonder if we shouldn't just build the whole display engine code, excluding >> downstream encoders (HDMI, DSI, TV) into one module. That would also fix the >> issue that DRM_SUN4I_BACKEND has to be built-in if DRM_SUN4I is built-in. >> That might be overkill though, given that one day we should be able to get >> rid of the frontend check. > > We can't really do that (or at least without rewriting a significant > part of the driver), since we can have only one > module_init/module_exit function per module, and we have one > per-hardware block. Right. That would require some serious plumbing to register all the drivers. ChenYu