Applies to: Three annotated documentary examples. The observations below are teaching cases, not captured EDID dumps or hardware tests.
What the path requires
- Record the display model/input and source OS/GPU.
- Compare offered modes directly and through the intermediate device without forcing custom timings.
- Use each exact product's pass-through/copy/emulation procedure.
What an offered mode means
A mode in the OS menu is evidence of a reported/accepted option in that state. It is not a sustained-signal measurement. An absent mode may reflect capability reporting, link limits, settings or an unsupported combination.
Dell Thunderbolt Dock WD22TB4 User Guide — Display resolution table · Dell U2720Q/U2720QM User’s GuideWorked documentary examples
1. U2720Q tells the host its identity
Documented outcome: Annotated report versus transport distinction
- Dell U2720Q, direct supported input; Plug-and-Play section.
- The manual says DDC provides the monitor's EDID to the computer.
- Annotation: this describes capability exchange, not a benchmark.
- Next compare the preset timing and actual input/USB-C priority before selecting a mode.
2. WD22TB4 table and a monitor's EDID
Documented outcome: Annotated table qualification
- Exact WD22TB4 link/port row and a connected monitor.
- Dell explicitly qualifies resolution support by monitor EDID.
- Annotation: a dock maximum does not force the display to advertise that timing.
- If missing, inspect the monitor input/timing and host link rather than replacing the EDID with an unsupported override.
3. VS221HDQ stores separate audio/video EDID choices
Documented outcome: Annotated switching-state example
- Exact VS221HDQ, manual revision 2014-03-27, EDID Copy section.
- The switch has Off, audio-only, video-only and audio+video copy positions.
- Annotation: retained capability data can differ from the currently attached display after a swap.
- Use only the exact manual’s EDID-copy procedure after confirming both endpoint capabilities; do not borrow another switch's instructions.
Your next useful observation
Record direct versus switched display identity, offered modes and sound format, with the exact switch EDID state.
Keep these limits
- No raw EDID was read from a device.
- No timing override, protected-content bypass or universal EDID cure.
Source documents, revisions and inspection methods
Dell Thunderbolt Dock WD22TB4 User Guide — Display resolution table
Dell · Online revision unavailable; retrieved page redirected to fr-be with English technical tables
HBR2/HBR3 USB-C and Thunderbolt tables; EDID note; HDMI/MFDP exclusion
Inspected 2026-10-23 by public_page. Primary HTML body and relevant table inspected; AI-assisted source reading, no independent human review or hardware validation.
Exact dock link/port selection, DSC and EDID qualifications.
Read the original sourceDell U2720Q/U2720QM User’s Guide
Dell · 2020-01 Rev. A00
USB-C Prioritization; Plug-and-Play; Preset Display Modes
Inspected 2026-10-23 by public_pdf_text. Primary PDF text and relevant table inspected; AI-assisted source reading, no independent human review or hardware validation.
Exact U2720Q modes and USB-C video/data priority; not U2723QE.
Read the original sourceVS221HDQ 2-Port HDMI Auto Switch — Instruction Manual
StarTech.com · Manual Revision 2014-03-27
Printed p.4: EDID Copy; positions 1–4
Inspected 2026-10-23 by public_pdf_text. Primary PDF text and relevant table inspected; AI-assisted source reading, no independent human review or hardware validation.
Exact historical switch has separate audio/video EDID-copy modes; not a generic switch rule.
Read the original sourceSource-documented education. Hardware behavior and independent human review have not been performed for these examples.