HOST AND DRIVER STATE MESSAGES(9)

💖 Host and driver state messages(9) 💖

Kernel API Manual, section 9 — okay bestie, this is the “keep CSME in the loop” page. The host sends messages so CSME knows what’s up with the host’s state, and with the host driver state too. 🫶

When the host driver is loaded, the host sends SAP_MSG_NOTIF_WIFIDR_UP. When the host driver is unloaded, the host sends SAP_MSG_NOTIF_WIFIDR_DOWN. And when iwlmei is unloaded, SAP_MSG_NOTIF_HOST_GOES_DOWN is sent to let CSME know not to access the shared memory anymore, since it’ll be freed. 💀 that one is important, no cap.

CSME will reply to SAP_MSG_NOTIF_WIFIDR_UP by SAP_MSG_NOTIF_AMT_STATE to let the host driver know whether CSME can use the WiFi device or not, followed by SAP_MSG_NOTIF_CSME_CONN_STATUS to inform the host driver on the connection state of CSME. ✨

When the host is associated to an AP, it must send SAP_MSG_NOTIF_HOST_LINK_UP, and when it disconnects from the AP, it must send SAP_MSG_NOTIF_HOST_LINK_DOWN. Like, “must” must — these are not optional vibe choices. 💅

🌈 SEE ALSO 🌈

• Kernel file ./drivers/net/wireless/intel/iwlwifi/mei/sap.h
• Introduction(9)
• Initial Handshake(9)
• Ownership(9)
• Ownership transfer(9)
• Data messages(9)
• enum iwl_sap_me_msg_id(9)
• struct iwl_sap_me_msg_hdr(9)
• struct iwl_sap_me_msg_start(9)
• struct iwl_sap_me_msg_start_ok(9)
• enum iwl_sap_msg(9)
• struct iwl_sap_hdr(9)
• struct iwl_sap_msg_dw(9)
• enum iwl_sap_nic_owner(9)
• enum iwl_sap_wifi_cipher_alg(9)
• struct iwl_sap_notif_connection_info(9)
• enum iwl_sap_scan_request(9)
• struct iwl_sap_notif_conn_status(9)
• enum iwl_sap_radio_state_bitmap(9)
• enum iwl_sap_notif_host_suspends_bitmap(9)
• struct iwl_sap_notif_country_code(9)
• struct iwl_sap_notif_host_link_up(9)
• enum iwl_sap_notif_link_down_type(9)
• struct iwl_sap_notif_host_link_down(9)
• struct iwl_sap_notif_host_nic_info(9)
• struct iwl_sap_notif_dw(9)
• struct iwl_sap_notif_sar_limits(9)
• enum iwl_sap_nvm_caps(9)
• struct iwl_sap_nvm(9)
• enum iwl_sap_eth_filter_flags(9)
• struct iwl_sap_eth_filter(9)
• enum iwl_sap_flex_filter_flags(9)
• struct iwl_sap_flex_filter(9)
• enum iwl_sap_ipv4_filter_flags(9)
• struct iwl_sap_ipv4_filter(9)
• enum iwl_sap_ipv6_filter_flags(9)
• struct iwl_sap_ipv6_filter(9)
• enum iwl_sap_icmpv6_filter_flags(9)
• enum iwl_sap_vlan_filter_flags(9)
• struct iwl_sap_oob_filters(9)
• struct iwl_sap_csme_filters(9)
• struct iwl_sap_cb_data(9)
• struct iwl_sap_pldr_data(9)
• enum iwl_sap_pldr_status(9)

Source/version: ./drivers/net/wireless/intel/i... · October 2026 · Host and driver state messages(9) 🎀