[Linux-aus] USB-C chargers

James Henstridge james at jamesh.id.au
Mon Nov 28 21:10:31 AEDT 2022

On Mon, 28 Nov 2022 at 14:58, Russell Coker via linux-aus
<linux-aus at lists.linux.org.au> wrote:
> https://www.austeamhk.com/products/30w-usb-c-power-adapter-charger-for-lenovo-x1-carbon-5th-gen
> I have a Thinkpad Carbon X1 Gen5 which shipped with a 65W USB-C PSU and which
> runs well with a 45W USB-C PSU.  The above advert and others like it imply
> that 30W is adequate to power that laptop.
> https://www.kogan.com/au/c/black-friday-sale-22-tech/shop/category/phones-accessories-smartphones-accessories-44025/?facet-features-furniture-filterable=GaN+Technology
> Kogan offered some deals on GaN chargers, the above is the one that's still on
> sale, they also had a 30W one for $10 which I bought expecting it to work with
> my Thinkpad, but it didn't.
> How do I work out why the charger didn't work?  If I buy the 68W version of
> that charger is it likely to work?  Could it be the USB-C - USB-C cables that
> I used (I tested 3 cables of different brands from my collection)?

You can sometimes find some information in /sys/class/typec as described here:


However, it really depends on what information the hardware exposes to
the OS. I've got an X1 Gen5, and only a small amount of that info is
exposed (at least on kernel 5.19: there's no ). I think most of the
USB-PD stuff is being handled in the firmware without the OS's

The spec sheet for the laptop seems to indicate that it won't fast
charge with the official 45W charger, so I suspect a 30W charger won't
cut it.



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