[SOLVED] Brightness bug on Samsung NPE350E7

business_kid · 08-10-2014, 01:12 PM

I'm blaming windows for this.

The screen comes on from suspend, hibernate or power down quite dim. I can get it sorted with this command

Code:

echo 1300 > /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight/brightness

But if I suspend or close the lid, it's back. I have an ssd with slackware-14.0, and a 600G hard drive with windows-8.0. I use slackware, and don't use uefi & windows 8. I kept the drive in case it needed to go back as warranty. Recently I updated the drive from windows-8.0 to 8.1 just because the update was there, and, knowing m$ as I do, I reckoned they would time out on that sort of thing. Windows-8.1 was supposed to fix the most abysmal failings of 8.0 anyhow. I was without the pc for 2 days while I fought with updates, and upgrades, and watched it do nothing. Seriously, things were quicker in the days of dialup. Now it has borked the brightness.

Any ideas? It must have fiddled something in the system settings, but I can't adjust that myself.

ntubski · 08-11-2014, 05:26 PM

By "brightness bug" you mean it's stuck on max brightness?

Hmm, I have a samsung n150, and I was using this script to control the backlight, but recently the script stopped having any effect; the brightness was locked to max. Changing it to use /sys/devices... instead makes it work again, so thanks

I don't think it's related to Windows; at various times Windows updated the graphics driver and its brightness was stuck at max, downgrading the driver fixed it on the Windows side, but that's always been independent of Linux control over backlight (also, the backlight control always works from the bootloader).

On the other hand, I am running Debian testing, so my kernel gets updated all the time; it seems likely the change resulted from that. Since you're on Slackware your config should be stable...

business_kid · 08-12-2014, 03:09 AM

My screen is a constipated, dim, twilight colour until I jack up the brightness. There has been a wrong setting passed over. When recovering from suspend, it comes up bright but the brightness is set and it goes dim again :-(.

I have a one liner in the path for the moment, but I don't like it.

ntubski · 08-16-2014, 09:50 AM

Quote:

Originally Posted by business_kid

My screen is a constipated, dim, twilight colour until I jack up the brightness.

Oh, that's different from what I had then.

A web search didn't turn up anything promising. Did you typo the model name? Searching for it returns only this thread.

business_kid · 08-16-2014, 02:02 PM

Thanks for the replies.

I have more or less figured that I must have closed off with windows on battery, and it dimmed the screen accordingly and put itś opinions in the setup somewhere. Now linux boots, reads that setting, and adjusts itself dim :-/. My solution is to put in the (spit!) windows-8.0/8.1 disk again and turn off with the power connected. I just have not had time to do it yet.

business_kid · 08-26-2014, 07:34 AM

Sorry to reawaken this thread, but. . .

I reinstalled the windows disk which caused the problem. It promptly fell on it's sword, and recovery/downgrades were called for. I can apparently check the C drive (sda4), but not sda 1-3:-//. So it's back to windows 8.0. Brightness fine in m$.

Now the brightness comes up fine. As resume finishes, or the graphics kernel module loads from a boot, the linux disk now adjusts the brightness super-dim, and I have to hack it back. When I run startx, it is again adjusted super-dim. Has anyone the remotest idea how this is happening?

erik2282 · 08-26-2014, 09:33 AM

Yes, I have a Samsung Laptop with Linux on it and have struggled a lot with the FN keys and brightness. I finally found that there a package called samsungtools that you can install and will make the FN keys work with the brightness.

Here the site where to download:

https://launchpad.net/samsung-tools

Its a tar file. I've only installed it on my laptop when it had Debian, and it worked perfectly. Now the laptop has OpenSuse and the FN keys with Brightness worked "out-of-the-box".

Good Luck!

P.S..... Windows 8 = yuck.

erik2282 · 08-26-2014, 09:36 AM

You may also want to install this for your Sammy:

https://code.google.com/p/easy-slow-down-manager/

Below is for Debian, maybe for Slackware its different but can maybe guide or help you in some way. I got it from https://wiki.debian.org/InstallingDe...Samsung%20N150

Quote:

Brightness & Fn-keys
Brightness not working out of the box.

To get brightness work (tested on Wheezy) :

1/ Modify Grub configuration : in /etc/default/grub, add acpi_backlight=vendor to GRUB_CMDLINE_LINUX_DEFAULT. eg. :

GRUB_CMDLINE_LINUX_DEFAULT="nosplash acpi_backlight=vendor"
2/ Update grub

update-grub
Some Fn-keys working :

volume up ok
volume down ok
Volume mute ok
Make them all working installing easy-slow-down-manager package and compiling samsung-tools :

# aptitude install linux-headers-`uname -r`
# dpkg -i easy-slow-down-manager-dkms_x.x.x_all.deb
# aptitude install xbindkeys dbus-python rfkill gettext
# tar xzf samsung-tools-x.x.x.tar.gz
# cd samsung-tools-x.x.x
# make
# make install

business_kid · 08-27-2014, 03:34 AM

Thank you very much.

Unfortunately, I don't have reliable access to the Fn keys. They worked on slackware, but the keyboard chip is borked. Alt & Fn keys misbehave. It actually went under warranty, but I needed the box too much at the time and let it slide. I use an external keyboard most of the time, but it doesn't have Fn keys, of course.

business_kid · 08-27-2014, 01:35 PM

SORTED!

I found that 'xrandr' didn't affect brightness, but 'xrandr --verbose' gave me twilight viewing, like a power down or suspend.

There's this little program nobody seems to know about called xbacklight supplied with slackware, and it sorted it. It adjusts the backlight everywhere. Permanently. As permanently as windows 8 upset it. Very simple, and problem solved. For me, xbacklight -inc 25 was about right.