DRIVER LOAD WHEN CSME OWNS THE DEVICE(9)

💖 Driver load when CSME owns the device 💖

hii bestie 🫶 welcome to the Kernel API Manual, section 9 — yes we're in the big-girl kernel docs today, and honestly? it's giving "my roommate won't give me the aux" but make it hardware 💅

🎀 DESCRIPTION 🎀

okay so picture this: the driver (iwlwifi) is getting loaded, but CSME owns the device 😭 not the vibe. when that happens, the driver will ask CSME to release the device through HW registers. sounds simple right? nope. CSME will release the device only in the case that there is no connection through the mei bus 🌸

so if there is a mei bus connection? CSME flat-out refuses to release the ownership on the device through the HW registers 💀 rude but okay. in that case, iwlwifi has to first request ownership using the SAP protocol. that's the move, that's the whole plan, no cap ✨

and here's the slay part: once iwlwifi requests ownership through the SAP protocol, CSME will grant the ownership on the device through the HW registers as well 👑 like yes queen, mutual respect.

but wait — there's lore 🦋 in order to request ownership over SAP, we first need to have an interface, which means we need to register to mac80211. and that can't happen before we get the NVM that contains all the capabilities of the device. reading the NVM usually requires loading the firmware… but that is impossible as long as we don't have ownership on the device 😭😭

the chicken and egg problem is real and it is personal fr fr 🐣🥚

so how do we break the loop? in order to solve this chicken and egg problem, the host driver can just get the NVM through CSME, which owns the device 😌💅 it can send SAP_MSG_NOTIF_GET_NVM, which will be replied by SAP_MSG_NOTIF_NVM with the NVM's content that the host driver needs. iconic. problem solved. we ate 🔥

✨ SEE ALSO ✨

kernel file — go read it, it's right there:

./drivers/net/wireless/intel/iwlwifi/mei/iwl-mei.h

and the whole friend group 🫶:

• Introduction(9)
• Life cycle(9)
• Memory layout(9)
• Concurrency(9)
• Probe and remove from mei bus driver(9)
• CSME behavior regarding the ownership requests(9)
• Driver load when CSME is associated and a session is active(9)
• Datapath(9)
• enum iwl_mei_nvm_caps(9)
• struct iwl_mei_nvm(9)
• enum iwl_mei_pairwise_cipher(9)
• enum iwl_mei_akm_auth(9)
• struct iwl_mei_conn_info(9)
• struct iwl_mei_colloc_info(9)
• enum iwl_mei_sap_version(9)
• iwl_mei_is_connected(9)
• iwl_mei_get_nvm(9)
• iwl_mei_get_ownership(9)
• iwl_mei_set_rfkill_state(9)
• iwl_mei_set_nic_info(9)
• iwl_mei_set_country_code(9)
• iwl_mei_set_power_limit(9)
• iwl_mei_register(9)
• iwl_mei_start_unregister(9)
• iwl_mei_unregister_complete(9)
• iwl_mei_set_netdev(9)
• iwl_mei_tx_copy_to_csme(9)
• iwl_mei_host_associated(9)
• iwl_mei_host_disassociated(9)
• iwl_mei_device_state(9)
• iwl_mei_pldr_req(9)
• iwl_mei_alive_notif(9)

and that's the tea, bestie 🍓 this lil page came from ./drivers/net/wireless/intel/i... and it's dated October 2026 — screenshot it, cite it, live by it 💜🧚✨