drm_helper_...ed_functions(9)

✨ NAME ✨

okay so this is the drm_helper_...ed_functions(9) page from the Kernel API Manual, and the function we're hyping up is drm_helper_disable_unused_functions — its whole thing is disable unused objects. that's the name, that's the game. 💅

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🌸 SYNOPSIS 🌸

void drm_helper_disable_unused_functions (struct drm_device *dev );

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🎀 ARGUMENTS 🎀

• dev — the DRM device. that's it, that's the whole argument list, and honestly? iconic. 💖

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✨ DESCRIPTION ✨

okay so picture this: drm_helper_disable_unused_functions literally walks through the entire mode setting configuration of dev. it removes any CRTC links of unused encoders, and it removes encoder links of disconnected connectors. then it disables all unused encoders and CRTCs — either by calling their disable callback if available, or by calling their dpms callback with DRM_MODE_DPMS_OFF. cleanup era fr fr. 🧹✨

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💀 NOTE 💀

this function is part of the legacy modeset helper library, and it will cause major confusion with atomic drivers. why? because atomic helpers guarantee to never call ->disable hooks on a disabled function, or ->enable hooks on an enabled functions. drm_helper_disable_unused_functions on the other hand throws such guarantees into the wind and calls disable hooks unconditionally on unused functions. not me being dramatic — that's literally the note, bestie. 😭💀

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/gpu/drm/drm_crtc_helper.c overview(9)
• drm_helper_encoder_in_use(9)
• drm_helper_crtc_in_use(9)
• drm_crtc_helper_set_mode(9)
• drm_crtc_helper_atomic_check(9)
• drm_crtc_helper_set_config(9)
• drm_helper_connector_dpms(9)
• drm_helper_resume_force_mode(9)
• drm_helper_force_disable_all(9)

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made with love from ./drivers/gpu/drm, dated October 2026 — that's the source/version + date sign-off, bestie. 🫶💖🎀