BL.4.5.0-32bit - How to increase display brightness beyond 100%, please?

madmax25 · 03-08-2019, 08:37 AM

Usually, on my little netbook, I can adjust the brightness of my display by pressing Fn+F4 or Fn+F5.

But even with the brightness at its maximum, the display is quite dark.

Is there a way to increase the maximum?

I already tried to edit

Code:

/sys/class/backlight/acpi_video0/max_brightness

from 8 (default) to let's say 10, but the file refuses to be edited, even as sudo.

Now, what can I do to increase the brightness of my display, please?

hemlocktree · 03-08-2019, 08:40 AM

i believe physically that highest you can get is the hidhest you can get re: limits. ther is no way to go beyond it as such. the screen can only put out so much and then that is it.

madmax25 · 03-08-2019, 09:11 AM

Ok, but then I wonder, how can it be, VLC can make videos much brighter?

Isn't there by any chance some tool capable of doing something similar for Bodhi?

hemlocktree · 03-08-2019, 09:24 AM

no clue. sorry.

RonCam · 03-08-2019, 04:03 PM

Quote:

Originally Posted by madmax25

...
I already tried to edit

Code:

/sys/class/backlight/acpi_video0/max_brightness

from 8 (default) to let's say 10, but the file refuses to be edited, even as sudo.

Just for comparison, on an eeePC, in the directories eeePC and intel_backlight we have max_brightness values of 15 and 125, respectively.

rbtylee · 03-08-2019, 04:20 PM

Quote:

Originally Posted by madmax25

...

I already tried to edit

Code:

/sys/class/backlight/acpi_video0/max_brightness

from 8 (default) to let's say 10, but the file refuses to be edited, even as sudo.

...

Root should be able to edit that file but you can not enter a value that the driver thinks does not exist.

Have you tried the backlight module?

ondoho · 03-10-2019, 06:38 AM

i think the max_brightness is a read-only value provided by the hardware. it's the maximum brightness possible.
the number does not reflect physical brightness; if it's 8, it means you can adjust brightness in 8 steps, no more.

there must be another file in that directory that you can echo a value between 0 and 8 into. as root.
sorry, i don't have a laptop atm so i can't be more precise.

the actual full brightness varies wildly between different (physical) screens, but you can only measure it from the outside.

VLC does not make it brighter; maybe there's just more contrast.

that said, it is possible that the desktop environments brightness adjustment thingymajick has gone haywire.
i suggest trying the command line trick again, maybe as described here.

madmax25 · 03-15-2019, 08:11 AM

@ rbtylee
Yes, I tried this module, but it is set to its maximum already.

@ ondoho
With the value of 8 I reached the maximum already, but I'm looking for a way to reach 9 or 10. Of course, without damaging the display.

In VLC, I can increase both brightness and contrast, but they affect only videos, not the system itself.

EDIT:
The xbacklight package doesn't give me more brightness than the backlight module does.

BW-userx · 03-15-2019, 08:36 AM

yes, you need to check your max brightness then adjust it accordingly,
max_brightness just tells you the max_brightness you can obtain, you need to adjust the brightness in the brightness file in the same directory. Adjust in increments of positive whole numbers to max_brightness. 0 ... max_brightness in the brightness file, not the max_brightness file.

on this laptop HP 8460p

Code:

$ ls   /sys/class/backlight/radeon_bl0
actual_brightness  brightness  max_brightness  subsystem  uevent
bl_power           device      power           type

Code:

$ cat   /sys/class/backlight/radeon_bl0/max_brightness
255

$ cat   /sys/class/backlight/radeon_bl0/brightness
253

example working script

Code:


#!/bin/bash
# for use to set laptop backlight on 
# hp 8460p with ATI graphics card, and hp 840 g2
# intel graphics chip
# Run as user with sudo permissions nopasswd
# should be able to use with passwd
#Monday Feb 18, 2019
 


if [[ -z $1 ]] ; then
	#check for hp 8460p setting or hp 840 g2 setting
	[[ -d /sys/class/backlight/radeon_bl0/brightness ]] && \
	{ sudo su -c ' echo 200 >  /sys/class/backlight/radeon_bl0/brightness' ; \
	  echo "Backlight Max setting is $(cat /sys/class/backlight/radeon_bl0/max_brightness)" ; \
	  echo "Backlight is set at $(cat /sys/class/backlight/radeon_bl0/brightness) " ; }
	  
	  [[ -d /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight ]] && \
	  { sudo su -c 'echo 800 > /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/brightness' ; \
		  echo "Backlight Max setting is $(cat /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/max_brightness)" ; \
		  echo "Backlight is set at $(cat /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/brightness)" ; }
else
	[[ -d /sys/class/backlight/radeon_bl0/brightness ]] && \
	{ sudo su -c ' echo $1 >  /sys/class/backlight/radeon_bl0/brightness' ; \
	  echo "Backlight Max setting is $(cat /sys/class/backlight/radeon_bl0/max_brightness)" ; \
	  echo "Backlight is set at $(cat /sys/class/backlight/radeon_bl0/brightness) " ; }
	  
	  [[ -d /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight ]] && \
	  { sudo su -c 'echo $1 > /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/brightness' ; \
		  echo "Backlight Max setting is $(cat /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/max_brightness)" ; \
		  echo "Backlight is set at $(cat /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight/brightness)" ; }
fi

the system will not allow a higher setting than what is in max_brightness. just locate that file then check to see what it is.

madmax25 · 03-15-2019, 04:13 PM

Quote:

Originally Posted by BW-userx

the system will not allow a higher setting than what is in max_brightness.

Indeed, that's my problem.

The max_brightness file only allows me to increase the brightness up to 8 and the Fn keys for the brightness do also work fine, but I can't get more brightness than the 8.
Unfortunately, even with the brightness set to its possible maximum of 8, I think, the display is too dark.

That's why I wanted to set a higher value in that max_brightness file, but the system doesn't allow me to edit it, not even as sudo, because I get the message "Cannot open file to overwrite."

rbtylee · 03-15-2019, 04:55 PM

Maybe it is something else other than brightness you are looking for, see How do I adjust the screen contrast?.

BW-userx · 03-15-2019, 05:38 PM

Quote:

Originally Posted by madmax25

Indeed, that's my problem.

The max_brightness file only allows me to increase the brightness up to 8 and the Fn keys for the brightness do also work fine, but I can't get more brightness than the 8.
Unfortunately, even with the brightness set to its possible maximum of 8, I think, the display is too dark.

That's why I wanted to set a higher value in that max_brightness file, but the system doesn't allow me to edit it, not even as sudo, because I get the message "Cannot open file to overwrite."

one you missed the part where that file,max_brightness is not made to be edited by user period.
the brightness file is. and that is the max limit that is set by the manufacturer of the item. so no you can not get over 100 percent on it.

being a net book the screen probably, I'd say is not a quality screen. get a better laptop with a better display, or look into seeing if that one can be upgraded with a better screen, or use it in a darker environment.

as far as watching movies as suggested, even I increase the brightness of some movies with what ever movie player I am using (MPV) then adjust the contrast to blend it into a nicer not so over powered washed out look.

In summery, there is no easy fix for this other than getting something that has a better display, or replacing your current with a better display. which can be done, if the manufacturer of that netbook has made other higher quality screens for it, as I have done it with this very laptop. taken out the screen and replaced with one that has a higher resolution. It is not a hard task.

if it is an old screen maybe getting a new one will look brighter. because it will not be as worn out.

other wise you're stuck with what you have, and you'll have to learn how to deal with it.

ondoho · 03-16-2019, 04:44 AM

Quote:

Originally Posted by madmax25

@ ondoho
With the value of 8 I reached the maximum already, but I'm looking for a way to reach 9 or 10. Of course, without damaging the display.

this is physically impossible.
please re-read my last post.

madmax25 · 03-16-2019, 06:57 AM

I know, it's the brightness file, that's meant for adjustments.
I was hoping, I could find a way to get a higher range of brightness.

Sad to learn, there's no software solution for this, and the only solution is to get another hardware.
But ok, I have to confess, this netbook is in fact very old (I got it back in 2008) and in all these years, the display probably has lost a part of its brightness anyway.

BW-userx · 03-16-2019, 07:18 AM

its called, or referred to as, "physical limitations"