On Fri, Nov 19, 2021 at 9:57 AM Alan J. Wylie alan@wylie.me.uk wrote:
Arnd Bergmann arnd@arndb.de writes:
Ah right, I ran into a similar thing on my randconfig builds, this is what I have applied locally but wasn't completely sure about yet, it may need additional 'select DRM_KMS_CMA_HELPER' to cover all instances:
With 5.15.3, I had these errors on *one* of my boxes with Nvidia drivers when building the nvidia drivers
Gentoo, nvidia-drivers-470.86
ERROR: modpost: "drm_atomic_helper_update_plane" [/work/tmp/portage/x11-drivers/nvidia-drivers-470.86/work/kernel/nvidia-drm.ko] undefined! ERROR: modpost: "drm_atomic_helper_connector_reset" [/work/tmp/portage/x11-drivers/nvidia-drivers-470.86/work/kernel/nvidia-drm.ko] undefined! ERROR: modpost: "drm_atomic_helper_page_flip" [/work/tmp/portage/x11-drivers/nvidia-drivers-470.86/work/kernel/nvidia-drm.ko]
To be honest, I'm not overly stressed out about breaking external modules. It is true that this driver only builds when CONFIG_DRM_KMS_HELPER is set, so you end up having to enable some other driver that selects it because the kernel doesn't know what symbols would be used. If you enable CONFIG_TRIM_UNUSED_KSYMS, you'd likely get additional problems here.
Before my patch, the kms helpers were selected by CONFIG_DRM_FBDEV_EMULATION in your .config, but this made no sense unless you also have a third-party module that uses it.
Arnd