DEV Community: Tomasz Giba

Investigation: Why I can't use my ThinkPad L14 fingerprint reader in Ubuntu 21.04?

Tomasz Giba — Sun, 01 Aug 2021 13:34:13 +0000

Running Ubuntu I wanted my Thinkpad fingerprint reader to work. It's not working out of the box and there are no first-page results when googling the problem.

So, I need to investigate.

This is the device my ThinkPad L14 has built-in:

➜  ~ lsusb | grep Fingerprint
Bus 002 Device 003: ID 27c6:55b4 Shenzhen Goodix Technology Co.,Ltd. Fingerprint Reader

OK. Device ID is 27c6:55b4 - got it

Now, most common lib that is used in fingerprint reading is libfprint.

Alright. Visiting its GitLab page, there's a link to list of unsupported devices: https://gitlab.freedesktop.org/libfprint/wiki/-/wikis/Unsupported%20Devices

..and my fingerprint reader is listed as unsupported:

..and libfprint developers are stating the following:

These are devices that are not supported. For most of them support is unlikely to ever happen, and if then only through reverse engineering efforts as vendors are only officially supporting a small subset of devices.

Oops.

Perhaps because it's a new device, the vendor "Shenzhen Goodix Technology" will support their devices in near future?

Nope..

Found this forum post where user asks Goodix for Linux support: https://developers.goodix.com/en/bbs/detail/2cc68cdf9f824e28b247f626c4a9374b

Well, it's 2021 and still no support.

Bummer Lenovo couldn't pressure their hardware providers to open-source the drivers or take care of this themselves. Shame.

How to get live currency rate(s) in command line

Tomasz Giba — Wed, 16 Dec 2020 10:30:23 +0000

You need curl and jq packages:

sudo apt install curl jq

You can do this using floatrates.com API. It's updated daily at midnight.

For USDPLN:

curl http://www.floatrates.com/daily/usd.json | jq .pln

..or for USDEUR:

curl http://www.floatrates.com/daily/usd.json | jq .eur

...and for EURUSD:

curl http://www.floatrates.com/daily/eur.json | jq .usd

and so on.

Lenovo ThinkPad L14 Problem booting Ubuntu 20.10 (Kernel 5.8) with Ryzen 7 Pro 4750U

Tomasz Giba — Tue, 27 Oct 2020 09:20:01 +0000

I got my ThinkPad L14 this year (2020)
When I upgraded my Ubuntu from 20.04 to 20.10 I encountered blank screen.

In booting logs I saw this error:

AMD-Vi: Unable to read/write to IOMMU perf counter

and inspired by this Stackoverflow answer https://stackoverflow.com/questions/62827591/amd-vi-unable-to-read-write-to-iommu-coun-problem-loading-x-509-certificate/63112560

I did the following:

in your GRUB boot menu select Advanced Ubuntu
select your previous (working) kernel version, mine was 5.4
log into Ubuntu
edit GRUB sudo vim /etc/default/grub
change this line GRUB_CMDLINE_LINUX="iommu=soft" and save the change
run sudo update-grub
restart and select your updated Ubuntu with kernel version 5.8

And it works!

How get int from base64'd number bytes representation in Go

Tomasz Giba — Tue, 15 Sep 2020 10:51:54 +0000

To make sure we won't overflow, we need math/big from Go

inputString := "Ag==" // base64'd byte representation of number 2

// first base64 -> bytes 
decodedBytes, _ := b64.StdEncoding.DecodeString(inputString)

// bytes -> big.Int
bigInt := new(big.Int)
bigInt.SetBytes(decodedBytes)

resultInt64 := bigInt.Int64() // == int64(2)
resultInt := int(resultInt64) // == int(2)

https://play.golang.org/p/DVxwwJHrbNu

How to display Go processes with their commands

Tomasz Giba — Wed, 22 Jul 2020 15:22:59 +0000

you have to have gops installed: https://github.com/google/gops

then:

gops | awk '{print $1}' | xargs ps -o pid,args