Messages in this thread | | | From | Arnd Bergmann <> | Date | Fri, 19 Nov 2021 10:33:38 +0100 | Subject | Re: [PATCH 5.15 808/917] drm: fb_helper: improve CONFIG_FB dependency |
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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
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