dm_test_mst_...set_mst_fail(9)

🌸 dm_test_mst_start_top_mgr_set_mst_fail(9) 🌸

okay bestie, welcome to the Kernel API Manual — this page is literally all about dm_test_mst_start_top_mgr_set_mst_fail, which is a KUnit test for the MST start failure path. yes, the failure path. we test the sad ending on purpose. iconic behavior honestly 💅

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✨ SYNOPSIS ✨

void dm_test_mst_start_top_mgr_set_mst_fail (struct kunit *test );

like, that's the whole signature. void in, void out. she doesn't return anything, she just does the thing 🎀

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🦋 ARGUMENTS 🦋

• test — the KUnit test context. that's it. that's the whole argument list. she's low maintenance 💖

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🌈 DESCRIPTION 🌈

okay so picture this, bestie: we've got a connector-backed link and an AUX channel that is failing (rude, but we set it up that way on purpose for the test 🫶).

On the non-boot path, the code calls drm_dp_mst_topology_mgr_set_mst(true). and that call? it tries to read the DPCD caps and fails, so it returns a negative error. which means the helper then returns false. 😭

so yeah — no cap, the whole point of this test is that the helper returns false under those conditions. the vibe check: negative error in, false out. periodt. 🔥

ngl this one is a "make the thing break so we know it breaks correctly" test. very main character energy of it. 👑

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💜 SEE ALSO 💜

so many siblings omg. this test lives in the Kernel file ./drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c, and here's the full fam in order, exactly as listed, no edits bestie:

dm_test_edid_extract_panel_id_basic(9),
dm_test_edid_extract_panel_id_zeros(9),
dm_test_apply_edid_quirks_dpcd_poweroff_delay(9),
dm_test_apply_edid_quirks_disable_fams(9),
dm_test_apply_edid_quirks_remove_sink_ext_caps(9),
dm_test_apply_edid_quirks_disable_colorimetry(9),
dm_test_apply_edid_quirks_skip_phy_ssc(9),
dm_test_apply_edid_quirks_unknown_noop(9),
dm_test_parse_edid_caps_null_edid(9),
dm_test_parse_edid_caps_null_caps(9), dm_test_parse_edid_caps_valid(9),
dm_test_parse_edid_caps_bad_checksum(9),
dm_test_parse_edid_caps_hdmi_frl(9),
dm_test_parse_edid_caps_hdmi_frl_dsc(9),
dm_test_parse_edid_caps_cea_audio(9),
dm_test_parse_edid_caps_cea_no_speaker(9),
dm_test_probe_acpi_edid_no_companion(9),
dm_test_read_acpi_edid_debug_mask_disabled(9),
dm_test_read_acpi_edid_non_panel_connector(9),
dm_test_read_acpi_edid_force_off(9),
dm_test_read_vbios_edid_non_embedded(9),
dm_test_read_vbios_edid_missing_callback(9),
dm_test_read_vbios_edid_callback_error(9),
dm_test_read_vbios_edid_missing_fake_edid(9),
dm_test_read_vbios_edid_invalid_fake_edid(9),
dm_test_read_vbios_edid_valid(9),
dm_test_freesync_pcon_whitelist_all_known(9),
dm_test_freesync_pcon_whitelist_not_in_list(9),
dm_test_freesync_pcon_whitelist_zero(9),
dm_test_populate_hdmi_scdc_present_true(9),
dm_test_populate_hdmi_scdc_present_false(9),
dm_test_populate_hdmi_frl_dsc_10bpc(9),
dm_test_populate_hdmi_frl_dsc_12bpc(9),
dm_test_populate_hdmi_frl_dsc_unknown_values(9),
dm_test_adaptive_sync_type_none_default(9),
dm_test_adaptive_sync_type_converter_no_conditions(9),
dm_test_adaptive_sync_type_converter_partial_conditions(9),
dm_test_adaptive_sync_type_pcon_whitelist(9),
dm_test_adaptive_sync_type_converter_nonwhitelist(9),
dm_test_helpers_is_fullscreen_returns_false(9),
dm_test_helpers_is_hdr_on_returns_false(9),
dm_test_get_max_frl_rate_3lanes_3gbps(9),
dm_test_get_max_frl_rate_3lanes_6gbps(9),
dm_test_get_max_frl_rate_4lanes_6gbps(9),
dm_test_get_max_frl_rate_4lanes_8gbps(9),
dm_test_get_max_frl_rate_4lanes_10gbps(9),
dm_test_get_max_frl_rate_4lanes_12gbps(9),
dm_test_get_max_frl_rate_unknown(9),
dm_test_dtn_log_buffer_accumulates(9),
dm_test_dtn_log_null_ctx_no_crash(9), dm_test_dp_read_dpcd_null_priv(9),
dm_test_dp_write_dpcd_null_priv(9), dm_test_dp_read_dpcd_success(9),
dm_test_dp_write_dpcd_success(9),
dm_test_execute_fused_io_null_dmub_srv(9),
dm_test_execute_synaptics_rc_command_write_success(9),
dm_test_execute_synaptics_rc_command_read_success(9),
dm_test_execute_synaptics_rc_command_write_fail(9),
dm_test_apply_synaptics_fifo_reset_wa_full(9),
dm_test_apply_synaptics_fifo_reset_wa_first_fail(9),
dm_test_write_dsc_enable_synaptics_enable_inactive(9),
dm_test_write_dsc_enable_synaptics_enable_active(9),
dm_test_write_dsc_enable_synaptics_disable_inactive(9),
dm_test_write_dsc_enable_synaptics_disable_active(9),
dm_test_write_dsc_enable_synaptics_enable_non_synaptics(9),
dm_test_dp_write_dsc_enable_routes_synaptics(9),
dm_test_mst_start_top_mgr_null_priv(9),
dm_test_mst_stop_top_mgr_null_priv(9),
dm_test_mst_start_top_mgr_boot(9),
dm_test_dp_write_hblank_reduction_false(9),
dm_test_get_dsc_max_slices_1_340(9),
dm_test_get_dsc_max_slices_2_340(9),
dm_test_get_dsc_max_slices_4_340(9),
dm_test_get_dsc_max_slices_8_340(9),
dm_test_get_dsc_max_slices_8_400(9),
dm_test_get_dsc_max_slices_12_400(9),
dm_test_get_dsc_max_slices_16_400(9),
dm_test_get_dsc_max_slices_unknown(9),
dm_test_init_panel_settings_pps(9), dm_test_init_panel_settings_dsc(9),
dm_test_override_panel_settings_debug_mask_disables_dsc(9),
dm_test_override_panel_settings_second_edp_disables_psr(9),
dm_test_fill_mst_payload_table_enable(9),
dm_test_fill_mst_payload_table_disable(9),
dm_test_fill_mst_payload_table_empty(9),
dm_test_submit_i2c_null_priv(9), dm_test_submit_i2c_success(9),
dm_test_submit_i2c_partial_transfer(9),
dm_test_dmub_aux_transfer_sync_hpd_discon(9),
dm_test_dp_update_branch_info_no_crash(9),
dm_test_mst_poll_pending_down_reply_no_crash(9),
dm_test_mst_clear_payload_alloc_table_no_crash(9),
dm_test_set_dcn_clocks_no_crash(9), dm_test_dmu_timeout_no_crash(9),
dm_test_smu_timeout_no_crash(9), dm_test_set_phyd32clk_no_crash(9),
dm_test_mst_update_branch_bandwidth_no_crash(9),
dm_test_mst_write_payload_alloc_table_null_ctx(9),
dm_test_mst_poll_for_act_null_ctx(9),
dm_test_mst_send_payload_alloc_null_ctx(9),
dm_test_mst_update_mgr_dealloc_null_ctx(9),
dm_test_is_dp_sink_present_null_priv(9),
dm_test_dmub_outbox_interrupt_control_null_dc(9),
dm_test_mst_enable_stream_features_aux_disabled(9),
dm_test_mst_enable_stream_features_writes_downspread(9),
dm_test_enable_periodic_detection_no_workqueue(9),
dm_test_enable_periodic_detection_updates_enable(9),
dm_test_enable_periodic_detection_schedules_work(9),
dm_test_read_mccs_caps_null_ctx(9), dm_test_read_mccs_caps_null_link(9),
dm_test_read_mccs_caps_no_vcp_code(9),
dm_test_read_mccs_caps_i2c_vcp_request(9),
dm_test_read_mccs_caps_hdmi_vcp_request(9),
dm_test_read_mccs_caps_legacy_pcon_vcp_request(9),
dm_test_read_mccs_caps_i2c_failure(9), dm_test_mccs_vcp_set_null_ctx(9),
dm_test_mccs_vcp_set_not_supported(9),
dm_test_mccs_vcp_set_null_link(9), dm_test_mccs_vcp_set_i2c_packet(9),
dm_test_mccs_vcp_set_i2c_failure(9),
dm_test_construct_old_payload_empty_list(9),
dm_test_construct_old_payload_intervening(9),
dm_test_write_payload_alloc_table_success(9),
dm_test_write_payload_alloc_table_enable(9),
dm_test_write_payload_alloc_table_disable(9),
dm_test_mst_stop_top_mgr_active(9),
dm_test_poll_for_act_no_mst_state(9), dm_test_poll_for_act_success(9),
dm_test_poll_for_act_status_failed(9),
dm_test_mst_send_payload_alloc_part2_fail(9),
dm_test_mst_update_mgr_dealloc_success(9),
dm_test_dp_write_dsc_enable_mst_no_aux(9),
dm_test_dp_write_dsc_enable_non_dp(9),
dm_test_dp_write_dsc_enable_mst_enable_decode_only(9),
dm_test_dp_write_dsc_enable_mst_enable_passthrough(9),
dm_test_dp_write_dsc_enable_mst_disable_decode_only(9),
dm_test_dp_write_dsc_enable_mst_disable_passthrough(9),
dm_test_dp_write_dsc_enable_sst_rx_enable(9),
dm_test_dp_write_dsc_enable_sst_rx_disable(9),
dm_test_dp_write_dsc_enable_pcon_enable(9),
dm_test_dp_write_dsc_enable_pcon_disable(9),
dm_test_dp_handle_test_pattern_no_pipe(9)

say hi to the whole family for me okay 🧚💜

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okay that's the whole page!! before you go — the tiny fine print at the bottom said this came from ./drivers/gpu/drm/amd/display/... and it's dated October 2026, and the manual name it's filed under is exactly that same dm_test_mst_...set_mst_fail(9). consider it your little signed autograph at the end of the page, bestie 🎀✨ slay, go run your tests 💅