If CONFIG_ROCKCHIP_ANALOGIX_DP is not set, the rockchip drm driver will fail to link: drivers/gpu/drm/rockchip/cdn-dp-core.o: In function `cdn_dp_connector_mode_valid': cdn-dp-core.c:(.text+0x1e1): undefined reference to `drm_dp_bw_code_to_link_rate' cdn-dp-core.c:(.text+0x1f4): undefined reference to `drm_dp_bw_code_to_link_rate' drivers/gpu/drm/rockchip/cdn-dp-core.o: In function `cdn_dp_pd_event_work': cdn-dp-core.c:(.text+0x138e): undefined reference to `drm_dp_channel_eq_ok' drivers/gpu/drm/rockchip/cdn-dp-reg.o: In function `cdn_dp_train_link': cdn-dp-reg.c:(.text+0xd5a): undefined reference to `drm_dp_bw_code_to_link_rate' The problem is that the DP-helper module has been replaced by the display-helper module. So the driver have to select it. Reported-by: Hulk Robot <hulkci@xxxxxxxxxx> Fixes: 1e0f66420b13("drm/display: Introduce a DRM display-helper module") Signed-off-by: Ren Zhijie <renzhijie2@xxxxxxxxxx> --- drivers/gpu/drm/rockchip/Kconfig | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/rockchip/Kconfig b/drivers/gpu/drm/rockchip/Kconfig index 5afab49dc4f2..eb9ffa9e357d 100644 --- a/drivers/gpu/drm/rockchip/Kconfig +++ b/drivers/gpu/drm/rockchip/Kconfig @@ -47,6 +47,8 @@ config ROCKCHIP_ANALOGIX_DP config ROCKCHIP_CDN_DP bool "Rockchip cdn DP" depends on EXTCON=y || (EXTCON=m && DRM_ROCKCHIP=m) + select DRM_DISPLAY_HELPER + select DRM_DISPLAY_DP_HELPER help This selects support for Rockchip SoC specific extensions for the cdn DP driver. If you want to enable Dp on -- 2.17.1