Power efficient expansion card that cuts connection when nothing is inserted?

Creators & Developers
1

I know that there already were several threads about power efficiency when DP/HDMI or other cards are connected and it slowly drains the battery.

Would it be possible to have a small bump-switch that would simply cut the power to the card itself if there is nothing inserted into it?
Something like a small tooth that is stressed when a person inserts the connector into the plug.
Something similar like in USB-type-B, but in the expansion card itself. It would connect a switch and it could turn the power to the card on.

Or for instance there could also be a on-off switch at the bottom/side to do it manually.

What do you think?

2

From what I have read the power isn’t used by the card only but by the system that recognises it as plugged in and that’s where the disconnect has to be.

So the card has to be invisible somehow

3

What I was thinking about was that the laptop has a connection similar to this:

USB -> Expansion card -> Monitor (not usbA/usbC cord)

So if I disconnect the monitor from the Expansion card then I saw some guides that told that it consumes less power than if an expansion card would be connected but idle.

So by having this switch we could disconnect the card by breaking connection for a pin that is checked.
And this would render the card disconnected.

This was what I was thinking.
And if you’d want to stop the ping process from the laptop itself then I don’t really know what to suggest because it has to be pinged in any case.
It will have to trigger at some point and there is no way to fully avoid it.
It could be reduced but not removed completely.

4

The power consumption issue isn’t with the card itself as @amoun alluded to. It is with the controllers and retimers not going into a suspend state when no display is connected. Or at least, that is what I have understood from reading this thread.

This isn’t to say that your idea wouldn’t work. It would. Just not for the reason you think. If you can disconnect the expansion card from the TB4 controller, then it might as well be unplugged/removed. So things will move into a suspend state as they should.

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5

It was based on a suggestion that somebody gave to disconnect the expansion cards to save battery.
So I kind of went there but I didn’t specify how it would work. It was based on someone else’s suggestions.

So if we could do that mechanically then the software would think there is actually nothing connected at all.

If this would save battery it would add a weak point to the cards. It’s a tradeoff.