drm_dp_mst_atomic_check(9)

💅 drm_dp_mst_atomic_check(9) — the Kernel API Manual, but make it make sense

okay so bestie, welcome to the kernel API manual 🎀 this one's a little function with a big job, and it lives right here in the display corner of the kernel. buckle up, we're doing MST atomic validation ✨

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🌸 NAME 🌸

drm_dp_mst_atomic_check — literally checks that the new state of an MST topology in an atomic update is valid 💖

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✨ SYNOPSIS ✨

int drm_dp_mst_atomic_check (struct drm_atomic_commit *state );

that's it. that's the whole vibe. one argument, one int return, no cap 🔥

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🫶 ARGUMENTS 🫶

• state — a Pointer to the new struct drm_dp_mst_topology_state. yes bestie, the new one, the fresh state, the main character state 👑

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🦋 DESCRIPTION 🦋

so what does it actually do? it checks the given topology state for an atomic update to make sure it's valid 😌 and no, it's not doing that alone — it calls drm_dp_mst_atomic_check_mgr for all MST managers in the atomic state, which is giving very much "i'm not doing group projects by myself" energy 🫶

and yes, this includes checking whether there's enough bandwidth to support the new timeslot allocations in the atomic update 💀 because running out of bandwidth is not cute and we are not doing that.

lowkey important: any atomic drivers supporting DP MST must make sure to call this after checking the rest of their state in their drm_mode_config_funcs.atomic_check callback. must. not "eh maybe." must. 🚨

See also: drm_dp_mst_atomic_check_mgr drm_dp_atomic_find_time_slots drm_dp_atomic_release_time_slots — the trio, the squad, the friend group 🌈

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⭐ RETURN ⭐

• 0 if the new state is valid 💚
• negative error code otherwise 😭

periodt. that's the whole return contract.

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👑 SEE ALSO 👑

okay this list is long and honestly it ate. every single one, in order, because we don't skip entries in this house 💅

Kernel file ./drivers/gpu/drm/display/drm_dp_mst_topology.c dp mst helper(9), Branch device and port refcounting(9), drm_dp_mst_get_mstb_malloc(9), drm_dp_mst_put_mstb_malloc(9), drm_dp_mst_get_port_malloc(9), drm_dp_mst_put_port_malloc(9), drm_dp_mst_topology_try_get_mstb(9), drm_dp_mst_topology_get_mstb(9), drm_dp_mst_topology_put_mstb(9), drm_dp_mst_topology_try_get_port(9), drm_dp_mst_topology_get_port(9), drm_dp_mst_topology_put_port(9), drm_dp_mst_dpcd_read(9), drm_dp_mst_dpcd_write(9), drm_dp_mst_connector_late_register(9), drm_dp_mst_connector_early_unregister(9), drm_dp_add_payload_part1(9), drm_dp_remove_payload_part1(9), drm_dp_remove_payload_part2(9), drm_dp_add_payload_part2(9), drm_dp_get_vc_payload_bw(9), drm_dp_read_mst_cap(9), drm_dp_mst_topology_mgr_set_mst(9), drm_dp_mst_topology_queue_probe(9), drm_dp_mst_topology_mgr_suspend(9), drm_dp_mst_topology_mgr_resume(9), drm_dp_mst_hpd_irq_handle_event(9), drm_dp_mst_hpd_irq_send_new_request(9), drm_dp_mst_detect_port(9), drm_dp_mst_edid_read(9), drm_dp_mst_get_edid(9), drm_dp_atomic_find_time_slots(9), drm_dp_atomic_release_time_slots(9), drm_dp_mst_atomic_setup_commit(9), drm_dp_mst_atomic_wait_for_dependencies(9), drm_dp_mst_root_conn_atomic_check(9), drm_dp_mst_update_slots(9), drm_dp_check_act_status(9), drm_dp_calc_pbn_mode(9), drm_dp_mst_dump_topology(9), drm_dp_mst_port_downstream_of_parent(9), drm_dp_mst_add_affected_dsc_crtcs(9), drm_dp_mst_atomic_enable_dsc(9), drm_dp_mst_atomic_check_mgr(9), drm_atomic_get_mst_topology_state(9), drm_atomic_get_old_mst_topology_state(9), drm_atomic_get_new_mst_topology_state(9), drm_dp_mst_topology_mgr_init(9), drm_dp_mst_topology_mgr_destroy(9), drm_dp_mst_register_i2c_bus(9), drm_dp_mst_unregister_i2c_bus(9), drm_dp_mst_is_virtual_dpcd(9), drm_dp_mst_aux_for_parent(9), drm_dp_mst_dsc_aux_for_port(9) 🌟

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and that's the page bestie 🎀 huge shoutout to the source at ./drivers/gpu/drm/display, dated October 2026, and to the manual itself, drm_dp_mst_atomic_check(9) — she's iconic, she's specific, she validates MST topologies and she does it flawlessly 💜 iykyk ✨🌸