drm_atomic_...eeds_modeset(9)

💅 drm_atomic_crtc_needs_modeset 💅

okay so bestie, welcome to the Kernel API Manual — yes this is a drm_atomic_...eeds_modeset(9) page, the title got a little truncated by the vibes, but we're here and we're slaying 🫶

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✨ NAME ✨

drm_atomic_crtc_needs_modeset — compute combined modeset need 🌸

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✨ SYNOPSIS ✨

bool drm_atomic_crtc_needs_modeset (const struct drm_crtc_state *state
);

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🎀 ARGUMENTS 🎀

• state — the drm_crtc_state for the CRTC, aka the main character of this whole function 💖

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🦋 DESCRIPTION 🦋

So to give drivers flexibility (and like, we love flexibility), struct drm_crtc_state has 3 booleans tracking whether the state CRTC changed enough to need a full modeset cycle, and those three iconique booleans are: mode_changed, active_changed and connectors_changed. This helper literally just combines these three to compute the overall need for a modeset for state. That's it. That's the whole function. no cap ✨

The atomic helper code sets these booleans, but drivers can and should change them appropriately to accurately represent whether a modeset is really needed. In general, drivers should avoid full modesets whenever possible — lowkey a lifestyle choice, highkey good advice 💅

For example: if the CRTC mode has changed, and the hardware is able to enact the requested mode change without going through a full modeset, the driver should clear mode_changed in its drm_mode_config_funcs.atomic_check implementation. See? Iconic. Effortless. No full modeset required 😌

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🌈 SEE ALSO 🌈

Bestie, buckle up, this reference list is long — but every single one of them matters, so we're listing them all fr fr 🫶

• Kernel file ./include/drm/drm_atomic.h
• struct drm_crtc_commit(9)
• struct drm_private_state_funcs(9)
• struct drm_private_obj(9)
• drm_for_each_privobj(9)
• struct drm_private_state(9)
• struct drm_atomic_commit(9)
• drm_crtc_commit_get(9)
• drm_crtc_commit_put(9)
• drm_atomic_commit_get(9)
• drm_atomic_commit_put(9)
• drm_atomic_get_old_crtc_state(9)
• drm_atomic_get_new_crtc_state(9)
• drm_atomic_get_old_plane_state(9)
• drm_atomic_get_new_plane_state(9)
• drm_atomic_get_old_connector_state(9)
• drm_atomic_get_new_connector_state(9)
• __drm_atomic_get_current_plane_state(9)
• for_each_oldnew_connector_in_state(9)
• for_each_old_connector_in_state(9)
• for_each_new_connector_in_state(9)
• for_each_oldnew_crtc_in_state(9)
• for_each_old_crtc_in_state(9)
• for_each_new_crtc_in_state(9)
• for_each_oldnew_colorop_in_state(9)
• for_each_new_colorop_in_state(9)
• for_each_oldnew_plane_in_state(9)
• for_each_oldnew_plane_in_state_reverse(9)
• for_each_new_plane_in_state_reverse(9)
• for_each_old_plane_in_state(9)
• for_each_new_plane_in_state(9)
• for_each_oldnew_private_obj_in_state(9)
• for_each_old_private_obj_in_state(9)
• for_each_new_private_obj_in_state(9)
• drm_atomic_crtc_effectively_active(9)
• struct drm_bus_cfg(9)
• struct drm_bridge_state(9)

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and that's the whole page, bestie!! mwah 💋 this little number lives over in ./include/drm and it's stamped October 2026 — so go forth, clear that mode_changed, and avoid full modesets like you avoid drama in the group chat 💖✨🎀🦋🌸