GUI Brightness Control missing on new XFCE

ToZ · 2014-10-10 18:31:27

Interesting that you are not getting any sort of backlight interface.

What is the make and model of your computer?
Is there a setting in your bios that enables/disables or changes backlight?
Have you checked for a bios update?

Can you also post back (inside of [ c o d e ] [ / c o d e ] tags (without the spaces)) your /var/log/dmesg log file?
Also, what are the results of:

cat /var/log/Xorg.0.log | grep -i backlight

ljharp · 2014-10-10 19:16:49

ToZ wrote:

Interesting that you are not getting any sort of backlight interface.
What is the make and model of your computer?
Is there a setting in your bios that enables/disables or changes backlight?
Have you checked for a bios update?
Can you also post back (inside of [ c o d e ] [ / c o d e ] tags (without the spaces)) your /var/log/dmesg log file?
Also, what are the results of:
cat /var/log/Xorg.0.log | grep -i backlight

HP/Compaq dc5750

I checked the bios, didn't see anything for 'backlight'. btw.... don't know if this matters or not, but I am using a video card w/DVI hookup.

I have not checked for a bios update.

Do you want the entire dmesg log? It's quite long.

No result on "cat/var/log/Xorg.0.log | grep -i backlight"

ToZ · 2014-10-10 19:24:35

ljharp wrote:

btw.... don't know if this matters or not, but I am using a video card w/DVI hookup.

It shouldn't affect the creation of a backlight interface.

I have not checked for a bios update.

Might be worth checking. It might solve the problem.

Do you want the entire dmesg log? It's quite long.

You can use pastebinit:

pastebinit /var/log/dmesg

...and post back the link that is generated.

ljharp · 2014-10-10 19:48:00

http://paste.ubuntu.com/8535127/

ToZ · 2014-10-11 02:36:16

Hmmm. Nothing backlight-related there. Can you try the acpi_backlight=video kernel parameter to see if it provides a backlight interface for you in /sys/class/backlight?

Otherwise, you may need to file a bug report for this. From Ubuntu Backlight Wiki Entry:

Backlight control does not work and there are no entries in /sys/class/backlight.
Neither the ACPI backlight driver nor any vendor specific driver were able to find a valid interface. Either requires a new vendor driver (which is unlikely) or the ACPI BIOS is broken (see below). Updates to the ACPI BIOS are rare as well but in some cases it is possible to work with upstream to extend the Linux side to handle some of that brokenness.

ljharp · 2014-10-11 12:42:47

This will need to wait until Monday when I get back into work. I'm not having an issue with brightness at home (which is a GOOD thing.... lol). I will continue to investigate the bios update from home though. I went to HP's site, and through the model number they list a bios updater that can be written to a boot CD. However..... these are all for Windows machines. My home PC is a dual boot, so I'll do some investigating about that a little later.

Thanks again ToZ for all your help, I think my brain would explode if I tried to handle this by myself.... lol.

ljharp · 2014-10-13 12:46:26

Ok..... here's the update.

I did a flash update on the BIOS, booted into Xubuntu, still no brightness control. I even looked around in the BIOS for a backlight setting, to no avail. Started at square one on the modifying the grub startup with different video configs, to no avail. Next thought ToZ?

ToZ · 2014-10-13 15:03:28

1. With the bios update, are there any backlight interfaces:

for interface in /sys/class/backlight/*; do echo -e "\n $interface"; cat $interface/{brightness,max_brightness,actual_brightness}; done

2. And your current kernel boot line:

cat /proc/cmdline

3. Have you tried the acpi_backlight=video kernel parameter? When you do, post back the results of:

cat /proc/cmdline

...when running with that boot parameter.

ljharp · 2014-10-13 15:48:19

ToZ wrote:

1. With the bios update, are there any backlight interfaces:
for interface in /sys/class/backlight/*; do echo -e "\n $interface"; cat $interface/{brightness,max_brightness,actual_brightness}; done
2. And your current kernel boot line:
cat /proc/cmdline
3. Have you tried the acpi_backlight=video kernel parameter? When you do, post back the results of:
cat /proc/cmdline
...when running with that boot parameter.

1. /sys/class/backlight/*
cat: /sys/class/backlight/*/brightness: No such file or directory
cat: /sys/class/backlight/*/max_brightness: No such file or directory
cat: /sys/class/backlight/*/actual_brightness: No such file or directory

2. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash video.acpi_osi=Linux

3. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash vt.handoff=7 acpi_backlight=video

ToZ · 2014-10-13 21:00:09

ljharp wrote:

2. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash video.acpi_osi=Linux

Please note that "video.acpi_osi=Linux" isn't a valid kernel parameter. It won't actually do anything.

3. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash vt.handoff=7 acpi_backlight=video

With this parameter, you still didn't get any directories/files in /sys/class/backlight?

ljharp · 2014-10-14 13:34:13

ToZ wrote:

ljharp wrote:
2. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash video.acpi_osi=Linux
Please note that "video.acpi_osi=Linux" isn't a valid kernel parameter. It won't actually do anything.
3. BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=e735b252-f4c6-499e-bf13-9a6fbea093a7 ro quiet splash vt.handoff=7 acpi_backlight=video
With this parameter, you still didn't get any directories/files in /sys/class/backlight?

I was actually 'grasping at straws' with that video.acpi_osi=Linux

And..... no, still no directories.

ToZ · 2014-10-14 17:44:01

I'm sorry but I have no more suggestions. Without a backlight interface, you will not be able to control the backlight. Its probably best to create a bug report with your distro and follow through there.

ljharp · 2014-10-14 17:55:29

ToZ wrote:

I'm sorry but I have no more suggestions. Without a backlight interface, you will not be able to control the backlight. Its probably best to create a bug report with your distro and follow through there.

That's ok. As always, thank you for your time and your wisdom ToZ. I'm sure we will meet again at some point in this forum. Take care my friend.

LJH

ljharp · 2014-10-14 18:03:49

I did find this -

http://ubuntuforums.org/showthread.php?t=1907928&page=5

I tried it, and it did change the brightness.... which is what I wanted. Now, my question would be.... will it stay that way at reboot?

ljharp · 2014-10-15 16:31:39

Nevermind, I figured it out by myself. cool

What I did was created a startup event with the terminal command to increase the brightness by 1.09. It's been a good and productive day. I also created a startup sound for my computer. big_smile

ToZ · 2014-10-15 18:47:08

Glad you got something working. "xrandr --brightness" isn't a true backlight brightness management utility, but at least its something. From the man page:

--brightness brightness
Multiply the gamma values on the crtc currently attached to the
output to specified floating value. Useful for overly bright or
overly dim outputs. However, this is a software only modifica‐
tion, if your hardware has support to actually change the
brightness, you will probably prefer to use xbacklight.

You can try "xbacklight", but I don't think it will work because it also relies on a valid backlight interface in /sys/class/backlight.

ljharp · 2014-10-15 19:04:37

Thanks ToZ!

The only reason I started looking for any brightness adjustment was because I maxed out on my screen display, and it still seemed just a tad dark. So this 'bump' works out great. big_smile

Last edited by ljharp (2014-10-15 19:04:58)

MountainDewManiac · 2014-10-17 10:21:05

Wait, DC5750? Are you using a CRT monitor? If so, those don't have backlights AFAIK; the tube provides the illumination. And they tend to dim as they age.

Regards,
MDM

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#26 2014-10-10 18:31:27

Re: GUI Brightness Control missing on new XFCE

#27 2014-10-10 19:16:49

Re: GUI Brightness Control missing on new XFCE

#28 2014-10-10 19:24:35

Re: GUI Brightness Control missing on new XFCE

#29 2014-10-10 19:48:00

Re: GUI Brightness Control missing on new XFCE

#30 2014-10-11 02:36:16

Re: GUI Brightness Control missing on new XFCE

#31 2014-10-11 12:42:47

Re: GUI Brightness Control missing on new XFCE

#32 2014-10-13 12:46:26

Re: GUI Brightness Control missing on new XFCE

#33 2014-10-13 15:03:28

Re: GUI Brightness Control missing on new XFCE

#34 2014-10-13 15:48:19

Re: GUI Brightness Control missing on new XFCE

#35 2014-10-13 21:00:09

Re: GUI Brightness Control missing on new XFCE

#36 2014-10-14 13:34:13

Re: GUI Brightness Control missing on new XFCE

#37 2014-10-14 17:44:01

Re: GUI Brightness Control missing on new XFCE

#38 2014-10-14 17:55:29

Re: GUI Brightness Control missing on new XFCE

#39 2014-10-14 18:03:49

Re: GUI Brightness Control missing on new XFCE

#40 2014-10-15 16:31:39

Re: GUI Brightness Control missing on new XFCE

#41 2014-10-15 18:47:08

Re: GUI Brightness Control missing on new XFCE

#42 2014-10-15 19:04:37

Re: GUI Brightness Control missing on new XFCE

#43 2014-10-17 10:21:05

Re: GUI Brightness Control missing on new XFCE

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