ufshcd_change_power_mode(9)

📦 version 7.3.1, in nixpkgs unstable

Okay bestie, settle in, because this one is from the Linux kernel API manual (man section 9, the kernel internals girlies) and it's literally about changing the power mode of a UFS link. Yes, that UFS. Universal Flash Storage. The vibe is immaculate, the gears are shifting, let's go 🎀

🌸 NAME 🌸

ufshcd_change_power_mode — Change UFS Link Power Mode 💫

🦋 SYNOPSIS 🦋

int ufshcd_change_power_mode (struct ufs_hba *hba , struct
       ufs_pa_layer_attr *pwr_mode , enum ufshcd_pmc_policy pmc_policy );

✨ ARGUMENTS ✨

  • hba — the per-adapter instance, aka the struct ufs_hba main character we're doing all this for 👑
  • pwr_mode — a pointer to the target power mode (gear/lane) attributes, so like, where we're headed 🎯
  • pmc_policy — the Power Mode change policy, the rules of the glow-up 🧚

💖 DESCRIPTION 💖

So this function handles the high-level sequence for changing the UFS link power mode. It's giving project manager energy, honestly — it orchestrates the whole thing:

  • it triggers the vendor-specific pre-change notification first (a lil heads-up text in the group chat 📲),
  • then it executes the DME (Device Management Entity) power mode change sequence — that's the actual main-event transformation 💅,
  • and, upon success, it triggers the vendor-specific post-change notification so everyone knows the glow-up is complete ✨

No cap, that's the entire high-level flow. Pre-change, DME change, post-change. Iconic, honestly.

🎀 RETURN 🎀

Returns 0 on success, and a non-zero error code on failure 😭 — so always check it, bestie, fr fr.

🌈 SEE ALSO 🌈

This is the part where the manpage just dumps the entire extended friend group on you. Every single one, no skips 🫶

Kernel file ./drivers/ufs/core/ufshcd.c and these legends:

ufshcd_enable_intr(9), ufshcd_disable_intr(9), ufshcd_print_trs_all(9), ufshcd_print_pwr_info(9), ufshcd_wait_for_register(9), ufshcd_get_intr_mask(9), ufshcd_get_ufs_version(9), ufshcd_is_device_present(9), ufshcd_get_tr_ocs(9), ufshcd_utrl_clear(9), ufshcd_utmrl_clear(9), ufshcd_get_lists_status(9), ufshcd_get_req_rsp(9), ufshcd_is_exception_event(9), ufshcd_reset_intr_aggr(9), ufshcd_config_intr_aggr(9), ufshcd_disable_intr_aggr(9), ufshcd_enable_run_stop_reg(9), ufshcd_hba_start(9), ufshcd_is_hba_active(9), ufshcd_pm_qos_init(9), ufshcd_pm_qos_exit(9), ufshcd_pm_qos_update(9), ufshcd_set_clk_freq(9), ufshcd_scale_clks(9), ufshcd_is_devfreq_scaling_required(9), ufshcd_pause_command_processing(9), ufshcd_resume_command_processing(9), ufshcd_scale_gear(9), ufshcd_devfreq_scale(9), ufshcd_hold(9), ufshcd_send_command(9), ufshcd_copy_sense_data(9), ufshcd_copy_query_response(9), ufshcd_hba_capabilities(9), ufshcd_ready_for_uic_cmd(9), ufshcd_get_upmcrs(9), ufshcd_dispatch_uic_cmd(9), ufshcd_wait_for_uic_cmd(9), __ufshcd_send_uic_cmd(9), ufshcd_send_uic_cmd(9), ufshcd_sgl_to_prdt(9), ufshcd_map_sg(9), ufshcd_prepare_req_desc_hdr(9), ufshcd_prepare_utp_scsi_cmd_upiu(9), ufshcd_prepare_utp_query_req_upiu(9), ufshcd_compose_devman_upiu(9), ufshcd_comp_scsi_upiu(9), ufshcd_upiu_wlun_to_scsi_wlun(9), ufshcd_queuecommand(9), ufshcd_dev_cmd_completion(9), ufshcd_exec_dev_cmd(9), ufshcd_init_query(9), ufshcd_query_flag(9), ufshcd_query_attr(9), ufshcd_query_attr_retry(9), ufshcd_query_attr_qword(9), ufshcd_query_descriptor_retry(9), ufshcd_read_desc_param(9), struct uc_string_id(9), ufshcd_read_string_desc(9), ufshcd_read_unit_desc_param(9), ufshcd_memory_alloc(9), ufshcd_host_memory_configure(9), ufshcd_dme_link_startup(9), ufshcd_dme_reset(9), ufshcd_dme_enable(9), ufshcd_dme_set_attr(9), ufshcd_dme_get_attr(9), ufshcd_dme_rmw(9), ufshcd_uic_pwr_ctrl(9), ufshcd_uic_tx_eqtr(9), ufshcd_send_bsg_uic_cmd(9), ufshcd_uic_change_pwr_mode(9), ufshcd_get_max_pwr_mode(9), ufshcd_dme_change_power_mode(9), ufshcd_config_pwr_mode(9), ufshcd_complete_dev_init(9), ufshcd_make_hba_operational(9), ufshcd_hba_stop(9), ufshcd_hba_execute_hce(9), ufshcd_link_startup(9), ufshcd_verify_dev_init(9), ufshcd_setup_links(9), ufshcd_lu_init(9), ufshcd_sdev_init(9), ufshcd_change_queue_depth(9), ufshcd_sdev_configure(9), ufshcd_sdev_destroy(9), ufshcd_scsi_cmd_status(9), ufshcd_transfer_rsp_status(9), ufshcd_uic_cmd_compl(9), ufshcd_compl_one_cqe(9), __ufshcd_transfer_req_compl(9), ufshcd_mcq_compl_pending_transfer(9), ufshcd_transfer_req_compl(9), ufshcd_disable_ee(9), ufshcd_enable_ee(9), ufshcd_enable_auto_bkops(9), ufshcd_disable_auto_bkops(9), ufshcd_force_reset_auto_bkops(9), ufshcd_bkops_ctrl(9), ufshcd_exception_event_handler(9), ufshcd_quirk_dl_nac_errors(9), ufshcd_abort_all(9), ufshcd_err_handler(9), ufshcd_update_uic_error(9), ufshcd_check_errors(9), ufshcd_tmc_handler(9), ufshcd_handle_mcq_cq_events(9), ufshcd_sl_intr(9), ufshcd_intr(9), ufshcd_issue_tm_cmd(9), ufshcd_issue_devman_upiu_cmd(9), ufshcd_exec_raw_upiu_cmd(9), ufshcd_advanced_rpmb_req_handler(9), ufshcd_eh_device_reset_handler(9), ufshcd_try_to_abort_task(9), ufshcd_abort(9), ufshcd_process_probe_result(9), ufshcd_host_reset_and_restore(9), ufshcd_reset_and_restore(9), ufshcd_eh_host_reset_handler(9), ufshcd_get_max_icc_level(9), ufshcd_find_max_sup_active_icc_level(9), ufshcd_scsi_add_wlus(9), ufshcd_create_device_id(9), ufshcd_quirk_tune_host_pa_tactivate(9), ufshcd_quirk_override_pa_h8time(9), ufshcd_add_lus(9), ufshcd_get_op_mode(9), ufshcd_probe_hba(9), ufshcd_async_scan(9), ufshcd_set_dev_pwr_mode(9), ufshcd_suspend(9), ufshcd_resume(9), ufshcd_system_suspend(9), ufshcd_system_resume(9), ufshcd_runtime_suspend(9), ufshcd_runtime_resume(9), ufshcd_remove(9), ufshcd_set_dma_mask(9), ufshcd_devres_release(9), ufshcd_alloc_host(9), ufshcd_init(9)

Lowkey a whole friend group in here. If you're looking for anything else UFS-shaped, it's probably in that list 💀

And that's the whole page, bestie! This one lives in the ./drivers/ufs/core directory, and the manual was dated October 2026 — mark your calendars 📅. Also, just so we're clear, that ufshcd_change_power_mode(9) header you saw at the top is literally the same title, so nothing new there, periodt 💅✨

📦 where this page comes from