t4_filter_field_shift(9)

💅 t4_filter_field_shift — the t4_filter_field_shift edition of the Kernel API Manual (section 9, bestie)

okay so picture this: you're deep in the kernel, section 9 of the manual, and you need to know where a filter field sits inside the Compressed Filter Tuple. That's literally it, that's the whole gig. Pull up a chair 🎀

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✨ NAME ✨

t4_filter_field_shift — calculate filter field shift. that's it, that's the function, and honestly? iconic of it.

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🦋 SYNOPSIS 🦋

int t4_filter_field_shift (const struct adapter *adap , int filter_sel );

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🌸 ARGUMENTS 🌸

• adap — the adapter. yeah. the adapter. that's the whole description, no notes 💀
• filter_sel — the desired field, taken from the TP_VLAN_PRI_MAP bits.

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👑 DESCRIPTION 👑

So what does it actually do? It returns the shift position of a filter field within the Compressed Filter Tuple. That's the whole return value, no cap.

And how do you tell it which field you want? You spec it via its selection bit within TP_VLAN_PRI_MAL (the filter mode). E.g. F_VLAN. iykyk 💅

lowkey yes the manpage says TP_VLAN_PRI_MAL up there in the description and TP_VLAN_PRI_MAP up in the arguments — I'm giving you both, character for character, because that's what the page says and I am not out here editing kernel docs on vibes alone 🫶

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🌈 SEE ALSO 🌈

the kernel file, bestie — go read the source, it's right here:

./drivers/net/ethernet/chelsio/cxgb4/t4_hw.c

and then the entire friend group, in order, fr fr:

t4_wait_op_done_val(9), t4_set_reg_field(9), t4_read_indirect(9), t4_write_indirect(9), t4_record_mbox(9), t4_wr_mbox_meat_timeout(9), t4_memory_rw_init(9), t4_memory_update_win(9), t4_memory_rw_residual(9), t4_memory_rw(9), t4_get_regs_len(9), t4_get_regs(9), t4_eeprom_ptov(9), t4_seeprom_wp(9), t4_get_raw_vpd_params(9), t4_get_vpd_params(9), t4_get_pfres(9), sf1_read(9), sf1_write(9), flash_wait_op(9), t4_read_flash(9), t4_write_flash(9), t4_get_fw_version(9), t4_get_bs_version(9), t4_get_tp_version(9), t4_get_exprom_version(9), t4_get_vpd_version(9), t4_get_scfg_version(9), t4_get_version_info(9), t4_dump_version_info(9), t4_check_fw_version(9), t4_flash_erase_sectors(9), t4_flash_cfg_addr(9), t4_load_fw(9), t4_phy_fw_ver(9), t4_load_phy_fw(9), t4_fwcache(9), fwcaps16_to_caps32(9), fwcaps32_to_caps16(9), t4_link_acaps(9), t4_link_l1cfg_core(9), t4_restart_aneg(9), t4_handle_intr_status(9), t4_slow_intr_handler(9), t4_intr_enable(9), t4_intr_disable(9), t4_config_rss_range(9), t4_config_glbl_rss(9), t4_config_vi_rss(9), t4_read_rss(9), t4_tp_fw_ldst_rw(9), t4_tp_indirect_rw(9), t4_tp_pio_read(9), t4_tp_pio_write(9), t4_tp_tm_pio_read(9), t4_tp_mib_read(9), t4_read_rss_key(9), t4_write_rss_key(9), t4_read_rss_pf_config(9), t4_read_rss_vf_config(9), t4_read_rss_pf_map(9), t4_read_rss_pf_mask(9), t4_tp_get_tcp_stats(9), t4_tp_get_err_stats(9), t4_tp_get_cpl_stats(9), t4_tp_get_rdma_stats(9), t4_get_fcoe_stats(9), t4_get_usm_stats(9), t4_read_mtu_tbl(9), t4_read_cong_tbl(9), t4_tp_wr_bits_indirect(9), init_cong_ctrl(9), t4_load_mtus(9), t4_get_chan_txrate(9), t4_set_trace_filter(9), t4_get_trace_filter(9), t4_pmtx_get_stats(9), t4_pmrx_get_stats(9), compute_mps_bg_map(9), t4_get_mps_bg_map(9), t4_get_tp_e2c_map(9), t4_get_tp_ch_map(9), t4_get_port_type_description(9), t4_get_port_stats_offset(9), t4_get_port_stats(9), t4_get_lb_stats(9), t4_mdio_rd(9), t4_mdio_wr(9), t4_sge_decode_idma_state(9), t4_sge_ctxt_flush(9), t4_read_sge_dbqtimers(9), t4_fw_hello(9), t4_fw_bye(9), t4_early_init(9), t4_fw_reset(9), t4_fw_halt(9), t4_fw_restart(9), t4_fw_upgrade(9), t4_fl_pkt_align(9), t4_fixup_host_params(9), t4_fw_initialize(9), t4_query_params_rw(9), t4_set_params_timeout(9), t4_set_params(9), t4_cfg_pfvf(9), t4_alloc_vi(9), t4_free_vi(9), t4_set_rxmode(9), t4_free_encap_mac_filt(9), t4_free_raw_mac_filt(9), t4_alloc_encap_mac_filt(9), t4_alloc_raw_mac_filt(9), t4_alloc_mac_filt(9), t4_free_mac_filt(9), t4_change_mac(9), t4_set_addr_hash(9), t4_enable_vi_params(9), t4_enable_vi(9), t4_enable_pi_params(9), t4_identify_port(9), t4_iq_stop(9), t4_iq_free(9), t4_eth_eq_free(9), t4_ctrl_eq_free(9), t4_ofld_eq_free(9), t4_link_down_rc_str(9), fwcap_to_fwspeed(9), lstatus_to_fwcap(9), t4_handle_get_port_info(9), t4_update_port_info(9), t4_get_link_params(9), t4_handle_fw_rpl(9), init_link_config(9), t4_prep_adapter(9), t4_shutdown_adapter(9), t4_bar2_sge_qregs(9), t4_init_devlog_params(9), t4_init_sge_params(9), t4_init_tp_params(9), t4_init_portinfo(9), t4_read_cimq_cfg(9), t4_read_cim_ibq(9), t4_read_cim_obq(9), t4_cim_read(9), t4_cim_write(9), t4_cim_read_la(9), t4_tp_read_la(9), t4_idma_monitor_init(9), t4_idma_monitor(9), t4_load_cfg(9), t4_set_vf_mac_acl(9), t4_read_pace_tbl(9), t4_get_tx_sched(9), t4_sge_ctxt_rd_bd(9), t4_i2c_rd(9), t4_set_vlan_acl(9), modify_device_id(9), t4_load_boot(9), t4_flash_bootcfg_addr(9)

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okay and for the little sign-off moment: this page lives at ./drivers/net/ethernet/chelsio... (the source line, cutely truncated exactly like the original, no I will not be fixing it), dated October 2026, and it's page t4_filter_field_shift(9) in the Kernel API Manual. that's the whole footer, bestie — slay, go read your Compressed Filter Tuple 💖✨