STRUCT MEI_DEVICE(9)

🌸 NAME 🌸

struct mei_device — MEI private device struct. This is the struct mei_device(9) page from the Kernel API Manual, bestie, and it's literally the home of MEI's private device struct. ✨

✨ SYNOPSIS ✨

Here's the whole struct, copied exactly — we do not play with code in this house 💅:

       struct mei_device {
           struct device *parent;
           struct device dev;
           struct cdev *cdev;
           int minor;
           struct list_head write_list;
           struct list_head write_waiting_list;
           struct list_head ctrl_wr_list;
           struct list_head ctrl_rd_list;
           u8 tx_queue_limit;
           struct list_head file_list;
           long open_handle_count;
           struct mutex device_lock;
           struct delayed_work timer_work;
           bool recvd_hw_ready;
           bool pg_blocked;
           bool read_fws_need_resume;
           wait_queue_head_t wait_hw_ready;
           wait_queue_head_t wait_pg;
           wait_queue_head_t wait_hbm_start;
           unsigned long reset_count;
           enum mei_dev_state dev_state;
           wait_queue_head_t wait_dev_state;
           enum mei_hbm_state hbm_state;
           enum mei_dev_pxp_mode pxp_mode;
           u16 init_clients_timer;
           enum mei_pg_event pg_event;
         #ifdef CONFIG_PM;
           struct dev_pm_domain pg_domain;
         #endif ;
           unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE];
           u32 rd_msg_hdr[MEI_RD_MSG_BUF_SIZE];
           int rd_msg_hdr_count;
           bool hbuf_is_ready;
           struct mei_dma_dscr dr_dscr[DMA_DSCR_NUM];
           struct hbm_version version;
           unsigned int hbm_f_pg_supported:1;
           unsigned int hbm_f_dc_supported:1;
           unsigned int hbm_f_dot_supported:1;
           unsigned int hbm_f_ev_supported:1;
           unsigned int hbm_f_fa_supported:1;
           unsigned int hbm_f_ie_supported:1;
           unsigned int hbm_f_os_supported:1;
           unsigned int hbm_f_dr_supported:1;
           unsigned int hbm_f_vt_supported:1;
           unsigned int hbm_f_cap_supported:1;
           unsigned int hbm_f_cd_supported:1;
           unsigned int hbm_f_gsc_supported:1;
           struct mei_fw_version fw_ver[MEI_MAX_FW_VER_BLOCKS];
           unsigned int fw_f_fw_ver_supported:1;
           unsigned int fw_ver_received:1;
           struct rw_semaphore me_clients_rwsem;
           struct list_head me_clients;
           unsigned long me_clients_map[BITS_TO_LONGS( MEI_CLIENTS_MAX)];
           unsigned long host_clients_map[BITS_TO_LONGS( MEI_CLIENTS_MAX)];
           bool allow_fixed_address;
           bool override_fixed_address;
           struct mei_dev_timeouts timeouts;
           struct work_struct reset_work;
           struct work_struct bus_rescan_work;
           struct list_head device_list;
           struct mutex cl_bus_lock;
           enum mei_dev_kind kind;
         #if IS_ENABLED(CONFIG_DEBUG_FS);
           struct dentry *dbgfs_dir;
         #endif ;
           enum mei_dev_reset_to_pxp gsc_reset_to_pxp;
           const struct mei_hw_ops *ops;
           char hw[];
        };

🫶 Members 🫶

Member-by-member vibe check, no skips, no cap:

• parent — device on a bus.
• dev — device object.
• cdev — character device pointer.
• minor — minor number allocated for device.
• write_list — write pending list.
• write_waiting_list — write completion list.
• ctrl_wr_list — pending control write list.
• ctrl_rd_list — pending control read list.
• tx_queue_limit — tx queues per client linit.
• file_list — list of opened handles.
• open_handle_count — number of opened handles.
• device_lock — big device lock.
• timer_work — MEI timer delayed work (timeouts).
• recvd_hw_ready — hw ready message received flag.
• pg_blocked — low power mode is not allowed.
• read_fws_need_resume — the FW status handler needs HW woken from sleep.
• wait_hw_ready — wait queue for receive HW ready message form FW.
• wait_pg — wait queue for receive PG message from FW.
• wait_hbm_start — wait queue for receive HBM start message from FW.
• reset_count — number of consecutive resets.
• dev_state — device state.
• wait_dev_state — wait queue for device state change.
• hbm_state — state of host bus message protocol.
• pxp_mode — PXP device mode.
• init_clients_timer — HBM init handshake timeout.
• pg_event — power gating event.
• pg_domain — runtime PM domain.
• rd_msg_buf — control messages buffer.
• rd_msg_hdr — read message header storage.
• rd_msg_hdr_count — how many dwords were already read from header.
• hbuf_is_ready — query if the host host/write buffer is ready.
• dr_dscr — DMA ring descriptors: TX, RX, and CTRL.
• version — HBM protocol version in use.
• hbm_f_pg_supported — hbm feature pgi protocol.
• hbm_f_dc_supported — hbm feature dynamic clients.
• hbm_f_dot_supported — hbm feature disconnect on timeout.
• hbm_f_ev_supported — hbm feature event notification.
• hbm_f_fa_supported — hbm feature fixed address client.
• hbm_f_ie_supported — hbm feature immediate reply to enum request.
• hbm_f_os_supported — hbm feature support OS ver message.
• hbm_f_dr_supported — hbm feature dma ring supported.
• hbm_f_vt_supported — hbm feature vtag supported.
• hbm_f_cap_supported — hbm feature capabilities message supported.
• hbm_f_cd_supported — hbm feature client dma supported.
• hbm_f_gsc_supported — hbm feature gsc supported.
• fw_ver — FW versions.
• fw_f_fw_ver_supported — fw feature: fw version supported.
• fw_ver_received — fw version received.
• me_clients_rwsem — rw lock over me_clients list.
• me_clients — list of FW clients.
• me_clients_map — FW clients bit map.
• host_clients_map — host clients id pool.
• allow_fixed_address — allow user space to connect a fixed client.
• override_fixed_address — force allow fixed address behavior.
• timeouts — actual timeout values.
• reset_work — work item for the device reset.
• bus_rescan_work — work item for the bus rescan.
• device_list — mei client bus list.
• cl_bus_lock — client bus list lock.
• kind — kind of mei device.
• dbgfs_dir — debugfs mei root directory.
• gsc_reset_to_pxp — state of reset to the PXP mode.
• ops — : hw specific operations.
• hw — hw specific data.

👀 SEE ALSO 👀

Kernel file ./drivers/misc/mei/mei_dev.h, plus the whole cross-reference squad:

• enum mei_dev_pxp_mode(9)
• enum mei_dev_reset_to_pxp(9)
• enum mei_cb_file_ops(9)
• enum mei_cl_io_mode(9)
• struct mei_dma_dscr(9)
• struct mei_me_client(9)
• struct mei_cl_cb(9)
• struct mei_cl_vtag(9)
• struct mei_cl(9)
• struct mei_hw_ops(9)
• enum mei_pg_event(9)
• enum mei_pg_state(9)
• struct mei_fw_version(9)
• enum mei_dev_kind(9)
• mei_data2slots(9)
• mei_hbm2slots(9)
• mei_slots2data(9)
• mei_fw_status_str(9)
• kind_is_gsc(9)
• kind_is_gscfi(9)

🫶 cute sign-off: source/version is ./drivers/misc/mei, dated October 2026, and this whole page is the struct mei_device(9) manual. Byeeee, go read some kernel headers 💖