g/av • Posted by u/rack_randy • 2 months ago

Screen goes blank when laptop lid closes during presentation — HDMI handshake issue?

This is a consistent problem at one client's conference room. When a presenter closes their laptop lid to set it aside (keeping it plugged into HDMI), the display goes blank and won't come back without unplugging and re-plugging. This happens maybe 50% of the time.

Room has an 85" display, a Crestron DM-TX-201-C transmitter, and a DM-RMC-100-STR receiver at the display. No HDMI extender — direct connection from transmitter to receiver.

Is this a HDMI EDID/HDCP handshake problem? Or a laptop driver/power management issue?

💬 3 replies

3 replies

Best New Old Controversial

u/dante_dave • 2 months ago

If the EDID minder doesn't fully solve it, an HDMI Detective or key digital EDID manager between the laptop and the DM transmitter solves it in hardware — stores the display EDID and presents it regardless of what the connected display is doing.

111

u/av_wizard • 2 months ago

Classic EDID management problem. When the laptop lid closes, the OS thinks the display is gone, drops the HDMI negotiation, and when the lid opens again, the handshake doesn't re-establish cleanly over the DM system. Crestron DM-TX has an EDID minder mode — check the web interface and make sure it's storing and presenting the display's EDID to the laptop even when the display isn't actively negotiating.

u/crestron_carl • 2 months ago

Also set the laptop power plan so "closing the lid" = "do nothing" instead of sleep. Most corporate IT departments have this locked, but ask them to push a policy exception for conference rooms. Hardware EDID management combined with software power settings usually fully resolves this.