I have a Latitude 7490 that I primarily run Kubuntu on but dual boot to Windows 10 for a few things that can't be done on Linux. I've had it for about a year and a half and am finally getting comfortable in the environment but still am working to learn the higher level stuff. I recently had to replace my laptop due to tornado damage but was able to save the hard drive and swapped it into an identical refurbished one from the same vendor where I got my first one, except this one has a thunderbolt port. It's a super nice option and I would love to ditch the barrel plug for charging but for some reason it is limiting the charge rate in Kubuntu to 40 watts. I have one of the new smart chargers from Anker and can see exactly what wattage, amps and voltage each device is drawing. During post and in Windows it draws 60 which is what the barrel plug delivers (apparently there's a 90 watt barrel plug option and Dell's documentation says TB3 can go up to 100 but I'd be happy with 60).
I've been digging around and can't find anything that would limit the negotiation in Linux, but since I can literally see it charging at 60w until the login screen pops up and then drop to 40w it's pretty obvious that something software related is limiting it. I tried updating the Bios and TB firmware but nothing changed on charge rate. Anyone have an idea of how to start tracking this down?
I've been digging around and can't find anything that would limit the negotiation in Linux, but since I can literally see it charging at 60w until the login screen pops up and then drop to 40w it's pretty obvious that something software related is limiting it. I tried updating the Bios and TB firmware but nothing changed on charge rate. Anyone have an idea of how to start tracking this down?
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