dm_mst_test_aux_result_eio(9)

💅 dm_mst_test_aux_result_eio — from the Kernel API Manual, bestie ✨

Okay so real talk, this one is a KUnit test in the DRM/AMD display corner of the kernel, and its whole personality is "error codes map to -EIO". Short page, big vibes, let's go 🫶

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✨ NAME ✨

dm_mst_test_aux_result_eio — HPD/unknown/protocol errors map to -EIO. That's it, that's the whole thesis 💅 no cap.

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🎀 SYNOPSIS 🎀

void dm_mst_test_aux_result_eio (struct kunit *test );

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🦋 ARGUMENTS 🦋

• test — the KUnit test context. It's the little container the test framework hands you so you can actually assert stuff, iykyk 🌸

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🌈 DESCRIPTION 🌈

So here's the situation. These four AUX result codes — and I'm listing them exactly, do not come for me:

• AUX_RET_ERROR_HPD_DISCON
• AUX_RET_ERROR_UNKNOWN
• AUX_RET_ERROR_INVALID_OPERATION
• AUX_RET_ERROR_PROTOCOL_ERROR

all map to -EIO. Every single one of them. They all ate and left no crumbs, and the test is literally just here to confirm that mapping holds 😭👑

That's the test. That's what it does. Periodt.

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👑 SEE ALSO 👑

The kernel file living its best life at:

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

And the whole friend group, the entire squad, every sibling test in the family 🎀:

• dm_mst_test_needs_dsc_aux_workaround_match(9)
• dm_mst_test_needs_dsc_aux_workaround_rev12(9)
• dm_mst_test_needs_dsc_aux_workaround_wrong_dev_id(9)
• dm_mst_test_needs_dsc_aux_workaround_wrong_rev(9)
• dm_mst_test_needs_dsc_aux_workaround_low_sink_count(9)
• dm_mst_test_needs_dsc_aux_workaround_zero_sink_count(9)
• dm_mst_test_pbn_divider_null_link(9)
• dm_mst_test_pbn_divider_uses_link_bandwidth(9)
• dm_mst_test_reset_connector_setting(9)
• dm_mst_test_retrieve_downstream_no_aux(9)
• dm_mst_test_retrieve_downstream_present(9)
• dm_mst_test_retrieve_downstream_aux_error(9)
• dm_mst_test_retrieve_branch_no_parent(9)
• dm_mst_test_retrieve_branch_reads_oui(9)
• dm_mst_test_aux_result_success(9)
• dm_mst_test_aux_result_ebusy(9)
• dm_mst_test_aux_result_timeout(9)
• dm_mst_test_aux_transfer_native_read(9)
• dm_mst_test_aux_transfer_native_write(9)
• dm_mst_test_aux_transfer_partial_write(9)
• dm_mst_test_aux_transfer_error_result(9)
• dm_mst_test_aux_transfer_hpd_discon_quirk(9)
• dm_mst_test_aux_transfer_non_ack_reply(9)
• dm_mst_test_fill_payload_flags_native_write(9)
• dm_mst_test_fill_payload_flags_native_read(9)
• dm_mst_test_fill_payload_flags_i2c_read_mot(9)
• dm_mst_test_fill_payload_flags_write_status(9)
• dm_mst_test_msg_ready_mask(9)
• dm_mst_test_select_esi_dpcd_legacy(9)
• dm_mst_test_select_esi_dpcd_esi(9)
• dm_mst_test_sideband_msg_ready_no_ready_bits(9)
• dm_mst_test_sideband_msg_ready_read_error(9)
• dm_mst_test_sideband_msg_ready_without_mst_state(9)
• dm_mst_test_down_rep_msg_ready_wrapper(9)
• dm_mst_test_initialize_dp_connector_edp(9)
• dm_mst_test_initialize_dp_connector_mst(9)
• dm_mst_test_atomic_best_encoder(9)
• dm_mst_test_create_fake_mst_encoders(9)
• dm_mst_test_atomic_check_no_old_crtc(9)
• dm_mst_test_detect_unregistered(9)
• dm_mst_test_fp_guarded_public_stubs(9)

Like, forty-one of them. It's giving family reunion 🧚💜

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Heads up bestie: this page is from the Kernel API Manual, and the source path got abbreviated down to ./drivers/gpu/drm/amd/display/... in the footer, dated October 2026. So if you need the full path, the SEE ALSO file section above has the real one, mwah 💖

Anyway, take care of yourself, read the source, and remember: -EIO is forever 🍓✨