dm_mst_test_..._dpcd_legacy(9)

✨ dm_mst_test_..._dpcd_legacy ✨

okay so this is a page from the Kernel API Manual (yes, the kernel has lore too 💅) and it's all about dm_mst_test_select_esi_dpcd_legacy — like, the whole page is named dm_mst_test_..._dpcd_legacy(9) up top but the actual star of the show has the full name, iykyk 🎀

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🌸 NAME 🌸

dm_mst_test_select_esi_dpcd_legacy — bestie, it's literally the pre-1.2 DPCD ESI address/length situation. that's the whole vibe. ✨

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🦋 SYNOPSIS 🦋

void dm_mst_test_select_esi_dpcd_legacy (struct kunit *test );

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💖 ARGUMENTS 💖

• test — the KUnit test context 🧚 like, the lil bubble this test lives inside, fr fr.

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👑 DESCRIPTION 👑

so for DPCD rev < 0x12 (the old-school era, no cap), the legacy DP_SINK_COUNT address/length pair gets selected. that's it, that's the whole plot 🫶 the way that this function just picks the vintage option and moves on… iconic.

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⭐ SEE ALSO ⭐

the kernel file, in all its glory:

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

and now the whole ✨friend group✨ of sibling tests, because they literally all show up together:

• 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_eio(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_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)

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lowkey a whole friend group of MST tests and this one's just the legacy-DPCD one. vibe check passed ✅

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and that's the page!! 🎀 source/version line is ./drivers/gpu/drm/amd/display/... and it's dated October 2026, so yeah, this manpage is from the future, slay 💜 bye bestie, go read the other 41 pages 🦋✨