Incorrect PD amperage negotiated on 90W supply?

I normally have my Framework 13 AMD laptop connected to a Dell U2720Q monitor (which is a 90W PD device). I recently noticed that the system (the Kubuntu 25.04 development release) seems to be reporting that the system is negotiating 60W PD instead. It should normally be reporting this from sensors, with 4.5A*20V=90W:

ucsi_source_psy_USBC000:004-isa-0000
Adapter: ISA adapter
in0:          20.00 V  (min =  +5.00 V, max =  +5.00 V)
curr1:         4.50 A  (max =  +3.00 A)

However, most of the time it reports the following instead:

ucsi_source_psy_USBC000:004-isa-0000
Adapter: ISA adapter
in0:          20.00 V  (min =  +5.00 V, max =  +5.00 V)
curr1:         3.00 A  (max =  +3.00 A)

3A*20V=60W. I’m not quite sure why this is happening. I don’t have any other 90W PD devices to try with the laptop, nor do I have any other laptop with which to try the monitor. Does anyone else see this happening?

Sounds like it might be working as designed

and consistent with other users’ experiences:

I don’t think that’s the same thing. The number reported by sensors seems to be the negotiated maximum amperage, not the amperage currently being drawn. The laptop was fully charged and idle when these numbers were captured.

The laptop will negotiate 100W and draw up to 4.5A on a 100W(or higher) power supply, when connected to a lower supply it’ll negotiate a lower PD rating, since 90W is not a standardized PD protocol, the laptop will negotiate 3.25A(draw 3.0A) or 3.0A(draw 2.7A)

Regardless of whether 90W is standard for PD or not, the behavior you are describing isn’t the behavior I am seeing. It does work at 4.5A sometimes, proving that it will negotiate that value on a 90W supply (or at least this particular one).

I also did a functional test, or at least as much of one as I can do without a USB power meter. I let the laptop discharge overnight and then plugged it back in this morning. It negotiated 3A and started charging the battery. Then, with all screens off, I checked power draw at the wall and got 70W. I then repeated the test while compiling something to fully load the CPU and still got 70W. I then replugged the USB-C connector until I got it to negotiate 4.5A and repeated the second test, now getting 90W of power at the wall. This proves both that the number reported by sensors is accurate and that the laptop is indeed making use of the extra power when 90W is negotiated.

I’ve also been doing some testing on the only other 90W PD supply I have, which is another Dell U2720Q at work. Oddly enough, it always seems to negotiate 4.5A (as it should) on that one. I guess something might be wrong with the first monitor or the cable or something. I’m going to do some more testing.