dm_test_dete...ps_writeback(9)

🦋 NAME 🦋

okay bestie, this is the dm_test_detect_mst_skips_writeback page from the Kernel API Manual, and the page header calls it dm_test_dete...ps_writeback(9) — yes, it’s truncated like that, not me being chaotic 💀.

dm_test_detect_mst_skips_writeback — Test writeback connectors are skipped. That’s the whole name, no cap.

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✨ SYNOPSIS ✨

void dm_test_detect_mst_skips_writeback (struct kunit *test );

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🫶 ARGUMENTS 🫶

• test — The KUnit test context. That’s it, that’s the argument 💅

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💀 DESCRIPTION 💀

okay so picture it: a writeback connector gets hit by the early continue before its dc_link is ever dereferenced. So leaving dc_link as NULL must not crash. Periodt. The whole test is literally about that not-crashing energy 🫶.

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🌈 SEE ALSO 🌈

first up, the Kernel file bestie:

• ./drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c

and here’s the full friend group — every single reference, no skips, no “I’ll read it later” 🙈:

• dm_test_subconnector_type_none(9), dm_test_subconnector_type_vga(9), dm_test_subconnector_type_dvi_converter(9), dm_test_subconnector_type_dvi_dongle(9), dm_test_subconnector_type_hdmi_converter(9), dm_test_subconnector_type_hdmi_dongle(9)
• dm_test_subconnector_type_mismatched(9), dm_test_subconnector_type_default_unknown(9), dm_test_content_type_no_data(9), dm_test_content_type_graphics(9), dm_test_content_type_photo(9), dm_test_content_type_cinema(9)
• dm_test_content_type_game(9), dm_test_content_type_unknown_defaults_no_data(9), dm_test_adjust_colour_depth_fits_at_888(9), dm_test_adjust_colour_depth_reduces_to_888(9), dm_test_adjust_colour_depth_10bpc_passes(9), dm_test_adjust_colour_depth_420_halves_clk(9)
• dm_test_adjust_colour_depth_420_reduces(9), dm_test_adjust_colour_depth_reduces_12bpc_to_10bpc(9), dm_test_adjust_colour_depth_16bpc_no_fallback(9), dm_test_adjust_colour_depth_none_fits(9), dm_test_adjust_colour_depth_invalid_depth(9), dm_test_output_color_space_default_rgb_full(9)
• dm_test_output_color_space_default_rgb_limited(9), dm_test_output_color_space_default_ycbcr709(9), dm_test_output_color_space_default_ycbcr601_limited(9), dm_test_output_color_space_bt601_y_only(9), dm_test_output_color_space_bt601(9), dm_test_output_color_space_bt709(9)
• dm_test_output_color_space_bt709_y_only(9), dm_test_output_color_space_oprgb(9), dm_test_output_color_space_bt2020_rgb(9), dm_test_output_color_space_bt2020_rgb_limited(9), dm_test_output_color_space_default_rgb_auto_hdmi_cta(9), dm_test_output_color_space_default_rgb_auto_hdmi_vga(9)
• dm_test_output_color_space_default_rgb_auto_dp_cta(9), dm_test_output_color_space_default_rgb_full_hdmi_cta(9), dm_test_output_color_space_bt2020_rgb_auto_hdmi_cta(9), dm_test_output_color_space_bt2020_ycc(9), dm_test_output_color_space_default_ycbcr709_y_only(9), dm_test_output_color_space_default_ycbcr601(9)
• dm_test_output_color_space_bt2020_ycc_rgb_encoding(9), dm_test_output_color_space_bt2020_ycc_rgb_encoding_limited(9), dm_test_output_color_space_bt2020_rgb_ycc_encoding(9), dm_test_convert_color_depth_bpc_mappings(9), dm_test_convert_color_depth_bpc_unknown(9), dm_test_color_depth_from_info_bpc8(9)
• dm_test_color_depth_from_info_bpc10(9), dm_test_color_depth_from_info_zero_bpc_defaults_888(9), dm_test_color_depth_from_info_requested_bpc_caps(9), dm_test_color_depth_from_info_y420_default(9), dm_test_color_depth_from_info_y420_10bpc(9), dm_test_color_depth_from_info_y420_12bpc(9)
• dm_test_color_depth_from_info_y420_16bpc(9), dm_test_color_depth_from_info_requested_odd_bpc(9), dm_test_color_depth_from_info_unsupported_bpc(9), dm_test_to_connector_type_hdmi(9), dm_test_to_connector_type_edp(9), dm_test_to_connector_type_lvds(9)
• dm_test_to_connector_type_rgb(9), dm_test_to_connector_type_dp(9), dm_test_to_connector_type_dp_mst(9), dm_test_to_connector_type_dvi_dvii(9), dm_test_to_connector_type_dual_link_dvii(9), dm_test_to_connector_type_dvi_dvid(9)
• dm_test_to_connector_type_dual_link_dvid(9), dm_test_to_connector_type_virtual(9), dm_test_to_connector_type_unknown(9), dm_test_is_duplicate_mode_empty_list(9), dm_test_is_duplicate_mode_match(9), dm_test_is_duplicate_mode_no_match(9)
• dm_test_is_duplicate_mode_same_size_different_clock(9), dm_test_encoder_crtc_mask_1(9), dm_test_encoder_crtc_mask_2(9), dm_test_encoder_crtc_mask_3(9), dm_test_encoder_crtc_mask_4(9), dm_test_encoder_crtc_mask_5(9)
• dm_test_encoder_crtc_mask_6(9), dm_test_encoder_crtc_mask_default(9), dm_test_aspect_ratio_no_data(9), dm_test_aspect_ratio_4_3(9), dm_test_aspect_ratio_16_9(9), dm_test_aspect_ratio_64_27(9)
• dm_test_aspect_ratio_256_135(9), dm_test_copy_crtc_timing_copies_all_fields(9), dm_test_copy_crtc_timing_leaves_non_crtc_fields(9), dm_test_decide_crtc_timing_scale_enabled(9), dm_test_decide_crtc_timing_matching_mode(9), dm_test_decide_crtc_timing_no_copy(9)
• dm_test_decide_crtc_timing_no_crtc_clock(9), dm_test_funcs_reset_sets_defaults(9), dm_test_funcs_reset_edp_abm_level(9), dm_test_funcs_reset_edp_abm_disabled(9), dm_test_atomic_dup_state_copies_fields(9), dm_test_fill_hdr_null_metadata(9)
• dm_test_fill_hdr_zeroes_output(9), dm_test_set_property_scaling_center(9), dm_test_set_property_scaling_aspect(9), dm_test_set_property_scaling_fullscreen(9), dm_test_set_property_scaling_none(9), dm_test_set_property_scaling_unchanged(9)
• dm_test_set_property_underscan_hborder(9), dm_test_set_property_underscan_vborder(9), dm_test_set_property_underscan_enable(9), dm_test_set_property_abm_sysfs_control(9), dm_test_set_property_abm_level_off(9), dm_test_set_property_abm_level_value(9)
• dm_test_set_property_unknown(9), dm_test_get_property_scaling_center(9), dm_test_get_property_scaling_aspect(9), dm_test_get_property_scaling_full(9), dm_test_get_property_scaling_off(9), dm_test_get_property_underscan_borders(9)
• dm_test_get_property_abm_sysfs_allowed(9), dm_test_get_property_abm_level(9), dm_test_get_property_abm_disabled_zero(9), dm_test_get_property_unknown(9), dm_test_highest_refresh_writeback_null(9), dm_test_highest_refresh_cached_base(9)
• dm_test_highest_refresh_preferred_mode(9), dm_test_is_freesync_video_mode_null_mode(9), dm_test_is_freesync_video_mode_match(9), dm_test_is_freesync_video_mode_no_match(9), dm_test_cacp_caps_unsupported_ip(9), dm_test_cacp_caps_excluded_ip_316(9)
• dm_test_cacp_caps_edp_oled_supported(9), dm_test_cacp_caps_lvds_oled_supported(9), dm_test_cacp_caps_non_edp_signal(9), dm_test_cacp_caps_lcd_panel(9), dm_test_set_panel_type_vsdb_oled(9), dm_test_set_panel_type_vsdb_miniled(9)
• dm_test_set_panel_type_dpcd_oled(9), dm_test_set_panel_type_dpcd_miniled(9), dm_test_set_panel_type_did_oled(9), dm_test_set_panel_type_did_lcd(9), dm_test_set_panel_type_vendor_lum_heuristic(9), dm_test_set_panel_type_defaults_to_lcd(9)
• dm_test_update_subconnector_dp_with_sink(9), dm_test_update_subconnector_dp_no_sink(9), dm_test_update_subconnector_non_dp_noop(9), dm_test_fbc_init_no_compressor(9), dm_test_fbc_init_non_edp(9), dm_test_fbc_init_already_allocated(9)
• dm_test_fbc_init_no_modes(9), dm_test_detect_mst_no_connectors(9), dm_test_detect_mst_non_mst_link(9), dm_test_detect_mst_branch_without_aux(9), dm_test_find_first_crtc_match(9), dm_test_find_first_crtc_no_match(9)
• dm_test_find_first_crtc_empty_state(9), dm_test_find_first_crtc_skips_null_ptr(9), dm_test_find_first_crtc_returns_first(9), dm_test_set_panel_type_samsung_miniled(9), dm_test_set_panel_type_samsung_below_threshold(9), dm_test_set_panel_type_default_lcd(9)
• dm_test_cacp_caps_edp_supported(9), dm_test_cacp_caps_lvds_supported(9), dm_test_cacp_caps_old_ip_unsupported(9), dm_test_cacp_caps_ip_3_1_6_unsupported(9), dm_test_cacp_caps_non_edp_lvds_unsupported(9), dm_test_cacp_caps_lcd_unsupported(9)
• dm_test_fill_stream_borders_zeroed(9), dm_test_fill_stream_rgb_defaults(9), dm_test_fill_stream_sync_polarity_positive(9), dm_test_fill_stream_sync_polarity_negative(9), dm_test_fill_stream_inherits_old_stream(9), dm_test_fill_stream_timing_from_crtc(9)
• dm_test_fill_stream_color_depth_requested_bpc(9), dm_test_fill_stream_content_type(9), dm_test_fill_stream_aspect_ratio(9), dm_test_fill_stream_encoding_from_caller_ycbcr420(9), dm_test_fill_stream_encoding_from_caller_ycbcr422(9), dm_test_fill_stream_encoding_from_caller_ycbcr444(9)
• dm_test_fill_stream_hdmi_ep_clamps_depth(9), dm_test_fill_stream_non_hdmi_ep_keeps_depth(9), dm_test_create_stream_fake_sink_success(9), dm_test_create_stream_sets_dm_context(9), dm_test_create_stream_virtual_signal(9), dm_test_create_stream_scaling_src(9)
• dm_test_create_stream_existing_sink(9), dm_test_detect_force_on(9), dm_test_detect_force_on_digital(9), dm_test_detect_force_off(9), dm_test_detect_sink_present(9), dm_test_detect_no_sink(9)
• dm_test_poll_dac_load_returns_cached(9), dm_test_late_register_non_dp_succeeds(9), dm_test_unregister_non_dp_noop(9), dm_test_destroy_minimal(9), dm_test_destroy_releases_dc_sink(9), dm_test_destroy_releases_dc_em_sink(9)
• dm_test_encoder_disable_noop(9), dm_test_atomic_check_edp_native_keeps_scaling(9), dm_test_atomic_check_lvds_non_native_enables_scaling(9), dm_test_atomic_check_non_mst_returns_zero(9), dm_test_hdmi_cec_unset_edid_no_notifier(9), dm_test_create_eml_sink_no_edid(9)
• dm_test_handle_edid_mgmt_dp_sets_link_caps(9), dm_test_handle_edid_mgmt_non_dp_leaves_caps(9), dm_test_funcs_force_no_edid(9), dm_test_validate_stream_null_stream(9), dm_test_to_encoder_no_encoder(9), dm_test_to_encoder_returns_attached(9)
• dm_test_native_mode_no_encoder(9), dm_test_native_mode_empty_probed_zeroes_clock(9), dm_test_native_mode_copies_preferred(9), dm_test_create_common_mode_overrides(9), dm_test_add_common_modes_non_edp_noop(9), dm_test_add_common_modes_edp_adds(9)
• dm_test_ddc_get_modes_null_edid(9), dm_test_add_fs_modes_no_preferred_mode(9), dm_test_add_freesync_modes_null_edid_noop(9), dm_test_i2c_func_returns_flags(9), dm_test_i2c_xfer_no_ddc_pin(9), dm_test_get_amd_vsdb_unsupported(9)
• dm_test_get_amd_vsdb_supported(9), dm_test_parse_hdmi_amd_vsdb_null_edid(9), dm_test_parse_hdmi_amd_vsdb_no_extensions(9), dm_test_parse_hdmi_amd_vsdb_no_cea_ext(9), dm_test_parse_displayid_vrr_null_edid(9), dm_test_parse_displayid_vrr_no_displayid(9)
• dm_test_parse_displayid_vrr_sets_range(9), dm_test_mode_valid_interlace_rejected(9), dm_test_mode_valid_dblscan_rejected(9), dm_test_hdmi_cec_set_edid_no_notifier(9), dm_test_s3_handle_hdmi_cec_suspend(9), dm_test_s3_handle_hdmi_cec_resume(9)
• dm_test_create_validate_stream_null_dm_state(9), dm_test_update_after_detect_mst_noop(9), dm_test_update_after_detect_sink_unchanged(9), dm_test_update_scaling_null_mode(9), dm_test_update_scaling_fullscreen_default(9), dm_test_update_scaling_rmx_full(9)
• dm_test_update_scaling_rmx_aspect_pillarbox(9), dm_test_update_scaling_rmx_aspect_letterbox(9), dm_test_update_scaling_rmx_center(9), dm_test_update_scaling_underscan(9)

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okay that’s the whole page, bestie 💖 — the footer source/version is ./drivers/gpu/drm/amd/display/..., it’s dated October 2026, and the footer is still serving dm_test_dete...ps_writeback(9). slay ✨