dm_test_val...llback_fails(9)

💅 dm_test_validate_dcc_cap_callback_fails — yes bestie, the whole name, we're doing this

okay so real talk, this page is from the Kernel API Manual, section 9, and the star of the show is dm_test_validate_dcc_cap_callback_fails. long name? yes. iconic? also yes. it's a KUnit test, it lives in the AMD display driver corner of the kernel, and it has exactly one (1) job. let's get into it 🎀

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✨ NAME ✨

dm_test_validate_dcc_cap_callback_fails — literally just verifying the callback failure path. that's it. that's the whole vibe check. 💅

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🌸 SYNOPSIS 🌸

void dm_test_validate_dcc_cap_callback_fails (struct kunit *test );

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🦋 ARGUMENTS 🦋

• test — the KUnit test context. the emotional support struct, if you will. 🫶

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💖 DESCRIPTION 💖

okay so the tea: this test verifies if validation fails when the DCC capability callback returns false.

that's the entire plot. no plot twists, no side quests. callback says false → validation should fail → test is happy. slay. ✨

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🔥 SEE ALSO 🔥

bestie. babe. bestie. there are so many siblings in this family and i'm not skipping a single one of them, we're listing every last one, hold my iced coffee 😭

Kernel file

./drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_plane_test.c

and now, the friend group 👑

dm_test_plane_is_video_format_known_video(9), dm_test_fill_blending_defaults(9), dm_test_fill_blending_premulti_alpha_format(9), dm_test_fill_blending_coverage_alpha_format(9), dm_test_fill_blending_global_alpha(9), dm_test_modifier_has_dcc(9), dm_test_modifier_gfx9_swizzle_mode(9), dm_test_get_plane_formats(9), dm_test_get_plane_modifiers(9), dm_test_fill_dc_scaling_info(9), dm_test_get_min_max_dc_plane_scaling(9), dm_test_get_cursor_position(9), dm_test_format_mod_supported(9), dm_test_fill_gfx12_plane_attributes_from_modifiers(9), dm_test_fill_gfx9_plane_attributes_from_modifiers(9), dm_test_helper_check_state_viewport_reject(9), dm_test_validate_dcc_disabled_returns_success(9), dm_test_validate_dcc_video_non_gfx12_fails(9), dm_test_validate_dcc_missing_cap_func_fails(9), dm_test_validate_dcc_not_capable_fails(9), dm_test_validate_dcc_success_and_scan_mapping(9), dm_test_validate_dcc_independent_64b_mismatch_fails(9), dm_test_add_modifier_appends_value(9), dm_test_add_modifier_grows_capacity(9), dm_test_add_modifier_noop_when_mods_null(9), dm_test_fill_gfx9_tiling_info_from_device_pre_10_3(9), dm_test_fill_gfx9_tiling_info_from_device_10_3_plus(9), dm_test_fill_gfx9_tiling_info_from_modifier_linear(9), dm_test_fill_gfx9_tiling_info_from_modifier_pre_nv(9), dm_test_fill_gfx9_tiling_info_from_modifier_nv(9), dm_test_get_format_info(9), dm_test_fill_blending_global_alpha_dcn42(9), dm_test_get_plane_formats_overlay_universal_cap(9), dm_test_get_plane_modifiers_gfx9(9), dm_test_get_plane_modifiers_rv(9), dm_test_get_plane_modifiers_rv_constant_encode(9), dm_test_get_plane_modifiers_gfx10_1(9), dm_test_get_plane_modifiers_gfx10_3(9), dm_test_get_plane_modifiers_gfx11_64k_first(9), dm_test_get_plane_modifiers_gfx11_256k_first(9), dm_test_get_plane_modifiers_gfx12(9), dm_test_fill_gfx9_plane_attributes_dcc(9), dm_test_fill_gfx9_plane_attributes_validate_fails(9), dm_test_fill_gfx9_plane_attributes_dcc_rbplus_64b_no_128bcl(9), dm_test_fill_gfx9_plane_attributes_dcc_rbplus_128b(9), dm_test_fill_gfx9_plane_attributes_dcc_rbplus_unconstrained(9), dm_test_fill_gfx9_plane_attributes_dcc_gfx9_64b(9), dm_test_fill_gfx9_plane_attributes_dcc_gfx9_unconstrained(9), dm_test_fill_gfx12_plane_attributes_block0(9), dm_test_fill_gfx12_plane_attributes_block_unconstrained(9), dm_test_fill_gfx12_plane_attributes_validate_fails(9), dm_test_fill_plane_buffer_attributes_video(9), dm_test_fill_plane_buffer_attributes_gfx12(9), dm_test_get_min_max_dc_plane_scaling_fp16(9), dm_test_helper_check_state_small_viewport_width(9), dm_test_helper_check_state_small_viewport_height(9), dm_test_helper_check_state_bottom_clipped_height(9), dm_test_helper_check_state_scaling_caps(9), dm_test_fill_dc_scaling_info_nv12_dcn1x(9), dm_test_fill_dc_scaling_info_plane_caps(9), dm_test_get_cursor_position_bad_size(9), dm_test_format_mod_supported_d_swizzle_reject(9), dm_test_atomic_async_check_rejects(9), dm_test_atomic_async_check_overlay_cursor(9), dm_test_atomic_check_no_dc_state(9), dm_test_atomic_check_missing_crtc_state(9), dm_test_atomic_check_helper_failure(9), dm_test_atomic_check_color_pipeline_conflict(9), dm_test_atomic_check_scaling_failure(9), dm_test_panic_flush_no_dc_state(9), dm_test_plane_reset_initializes_state(9), dm_test_plane_duplicate_state_copies_fields(9), dm_test_plane_destroy_state_minimal(9)

like i said. every single one. not me being thorough or whatever 💀✨

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ngl, if you came here looking for options or flags, there aren't any — this is a function, not a command. go touch some struct kunit *test instead 🧚

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and that's the whole page, bestie 🌈 one last lil sign-off: this one shipped from the kernel source tree at ./drivers/gpu/drm/amd/display/..., dated October 2026, and yes the footer still calls it dm_test_val...llback_fails(9) because even the manpage got tired of typing the whole thing 💖 periodt 🎀