Starbook MK V: Excessive Power Draw from USB-C Display

[stan-janssen]

When I connect my StarBook MK V to a Dell S2719DC over USB-C, the monitor shuts down the connection with an "Excessive Power Draw from connected device" warning. The monitor is capable of delivering 45W PD, and I think the laptop want to draw 65W.

My other laptop, a Thinkpad T15, works fine with this display.

Could it be that the Starbook does not take into account the maximum power delivery from the USB-C power source? Would it be possible to include this functionality?

At the moment, I cannot use this display with this laptop when the laptop is not connected to its own power brick over the barrel jack.

[Sean-StarLabs]

Which variant and firmware versions?

[stan-janssen]

This is the Intel i7 variant with firmware version 8.15.

[Sean-StarLabs]

What EC version? (cat /sys/class/dmi/id/ec_firmware_release)

[stan-janssen]

$ cat /sys/class/dmi/id/ec_firmware_release
1.3

[Sean-StarLabs]

Thanks - that's fine, we use 28W PD monitors here without an issue. You could try putting it into power save, as that'll limit the max power draw to about 30W

[stan-janssen]

Yes, that seems to work! Thanks.

It does require rebooting though (at least, that is what the Coreboot application tells me); is there something that can be done to auto-detect the max power from the power source and adjust the laptop's power draw accordingly?

[Sean-StarLabs]

Not in coreboot; AMI can

[stan-janssen]

Is this something that I should report to the Coreboot developers or is that not helpful?

https://ticket.coreboot.org/projects/coreboot

[Sean-StarLabs]

It wouldn't change anything - coreboot avoids SMM, which would be needed for this, and it's tracking even further away from using it. It's just how coreboot is.