Screen brightness

Hardware Librem 13/15
1

I have a Librem 15 v3. I would like to know how many nits the display is? I have looked around online but i can’t seem to find a definite number anywhere.

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2

30!
I just kidding, but what is this for? Its less then modern screens with HDR or tv and its only to beat sometimes daylight. We just thought about it to save energy and have a readable screen at fu… ing daiylight in summer. And if really like to use it blind in summer light - just add a blind version with voice interaction to your favorite programs or terminal commands - and you will be on the save side.

The same with a broken window and ssh connection to your phone. :wink:

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3

I am happy with the quality of this screen but i am looking to buy a refurbished Dell or Lenovo laptop and i would like to know how many nits is good. Most of the models i see are 220 to 250 nits of brightness. If that is what this laptop has i will be happy with that. If my Librem 15 v3 is 300 nits, i may not be happy with 220 nits. That’s why i am curious.

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4

First, you have to find EDID information for the LCD panel:

sudo cat /sys/devices/pci*/0000:*/drm/card*/card*/edid

Manufacturer and model is what you want to know, then you can find data sheets/specs for the panel. This would likely tell you the information you are looking for (I know nothing about colorimetry and all that…)
I own a Librem 15 v4 and I could find out that the specific panel for my laptop is: Samsung 156FL02-101. Plenty of information about this panel found with search engines.

Caveat: I don’t know if the L15 v3 also had a 4kUHD panel. Neither do I know if both models had the same panel/manufacturer. On top of that, it could be that there were different sourcing for the same laptop model.

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5

Or let’s say that you have worked out what pathname(s) all those wildcards ultimately give you

sudo edid-decode pathname

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6

The Librem 15 v3 does not have a 4k panel. It’s a 1920 x 1080 matte display @ 60Hz. The best i can find is a very detailed review of the Librem 13 v3 on NotebookCheck. It says the 1080p IPS display of that model is roughly 350 nits, although they say overall it’s a bright screen with poor contrast. I assume the 15" version would be similar.

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7

I wouldn’t make that assumption. I would recommend following the procedure and commands given, in order to get the Manufacturer and Model, and then looking for the datasheet.

Edit:

Here’s a shell script to run as root

#!/bin/bash

for f in /sys/devices/pci*/0000:*/drm/card*/card*/edid ; do
	cd `dirname $f`
	pwd
	edid-decode edid | grep -E 'Manu|Model'
done
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8

This laptop is currently running Windows 10, not Linux, so i can’t run the script. The laptop was given to me by my brother who uses Linux exclusively.

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9

Then if you want to pursue it rigorously, you would need to make a Live Boot USB flash drive of any suitable distro, Live Boot the laptop, and run the script that way. Or if your sensible brother :wink: uses Linux exclusively, I expect you could borrow a Live Boot USB flash drive from him.

It is also possible that Windows would display the Manufacturer and Model of the panel somewhere but I surely would not be able to tell you where to find that information under Windows.

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I have a basic understanding of Linux so i can make a bootable USB with Mint.

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