Power detection issue in slackware 14.2 (laptop connected and charging but screen is dim)
SlackwareThis Forum is for the discussion of Slackware Linux.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Power detection issue in slackware 14.2 (laptop connected and charging but screen is dim)
below is the issue i face:
my adapter is plugged to my system, but still when i switch it on, i face a dimlit screen (brightness is very less)
i have to manually switch off and switch on my plug switch (and my monitor is lit up again properly to the right settings)
the laptop is being charged properly and i have tested with ON & OFF state and it is being detected correctly...the only issue is when i boot i get a low light and need to manually switch off and on my adapter switch to get a normal well lit display
Code:
cat /sys/class/power_supply/AC/online shows 0 (when unplugged) and 1 (when plugged)
Last edited by nitecrawler; 09-23-2016 at 12:34 PM.
keys as i have my laptop keyboard disabled on startup....only my usb keyboard works on startup which doesnt have the brightness keys to test the same...
i can control my brightness
Code:
inserting into /sys/class/backlight
but i am looking for auto-detection of adapter and resume brightness and vice-versa...
if i switch my laptop on, get the same brightness even if i unplug later (screen doesnt goes to dim state)
nitecrawler,
Is this a new problem that started after some kind of software update or upgrade?
My first advice is to check your BIOS for screen brightness settings.
Also, in my experience, it's very unusual for a laptop's AC adapter to have a switch on it.
Are you using the manufacturer approved AC adapter?
nitecrawler,
Is this a new problem that started after some kind of software update or upgrade?
well, i had upgraded to 14.2 recently, but not really sure if it was there before or popped up after the upgradation
Quote:
Originally Posted by STDOUBT
Also, in my experience, it's very unusual for a laptop's AC adapter to have a switch on it.
Are you using the manufacturer approved AC adapter?
yes, it is the manufacturer AC adapter...and no, there is no switch for the adapter, what i meant was the power source switch (the switch besides the socket i plug my adapter to)
So are you going to go ahead and recompile your DSDT?
Another option might be to upgrade the BIOS on your laptop, assuming there is a "fixed" one available. It does look like you're dealing with a firmware bug.
It might also be advisable to reboot to another (older) kernel if you have one installed to see if the problem is some kind of regression in your currently-working kernel firmware.
and it gets me to max brightness everytime i boot....( use redshift so it doesnt burn my eyes and thats precisely why i need max brightness )
Quote:
Originally Posted by STDOUBT
So are you going to go ahead and recompile your DSDT?
i need to spend time reading through them before i try compiling...understand dsdt better and so on....
Quote:
Originally Posted by STDOUBT
Another option might be to upgrade the BIOS on your laptop, assuming there is a "fixed" one available. It does look like you're dealing with a firmware bug.
dont know how to do this either....unless i am sure a "fixed" bios is available (by googling more and more), i am not going to interfere with bios as of now....
Quote:
Originally Posted by STDOUBT
It might also be advisable to reboot to another (older) kernel if you have one installed to see if the problem is some kind of regression in your currently-working kernel firmware.
i do not have an older verison but a newer version yes....shall boot into it and check but for now i need to get some rest and come back later on this.....
That will do for your machine. An example of more general solution:
Code:
cd /sys/class/backlight
for i in $(ls); do
if [ -e $i/max_brightness ]; then
if [ -e $i/brightness ]; then
cat $i/max_brightness > $i/brightness
fi
fi
done
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.