Screen brightness will not change on netbook install
Hi,
I just installed Slackware 13.37 on my netbook, and the screen brightness is way too dim. Control + up/down does nothing, and neither does the brightness slider in KDE. I tried in fluxbox also, and it's the same. Can anyone help me? I am brand new to Slackware, and I can't see well enough to learn what I am doing! And my eyes are killing me. Thanks! Edit: Oh, my netbook is a Samsung N145 Plus. I see some solutions for the problem under Ubuntu, but I have no idea how to extend them to Slackware. |
Your post is extremely sparse on usable info. When in doubt, provide too much rather than too little.
That said, a bit of digging shows that the innards of your netbook is somewhat similar to my Asus 1001P. I'll assume what worked for me might work for you:
If that doesn't do the trick, give us more info. Tell us exactly what you've tried & what degree of success/failure each attempt has given. Provide a snippet of 'lspci -vv' (only the section regarding the 'VGA compatible controller' is necessary in this case). |
Until you can verify a permanent solution how about trying 'xbacklight'
guff@guff:/usr/bin$ xbacklight --help usage: xbacklight [options] where options are: -display <display> or -d <display> -help -set <percentage> or = <percentage> -inc <percentage> or + <percentage> -dec <percentage> or - <percentage> -get -time <fade time in milliseconds> -steps <number of steps in fade> guff@guff:/usr/bin$ XBACKLIGHT(1) XBACKLIGHT(1) NAME xbacklight - adjust backlight brightness using RandR extension SYNOPSIS xbacklight [-help] [-display display] [-get] [-set percent] [-inc per- cent] [-dec percent] DESCRIPTION Xbacklight is used to adjust the backlight brightness where supported. It finds all outputs on the X server supporting backlight brightness control and changes them all in the same way. |
Quote:
If you wanted to know something about my computer's "innards," all you had to do was ask and I would have thankfully provided it. There is no need for snippiness. I don't know what gave you the idea that I had tried several things with differing degrees of success and failure that I for some reason was withholding. As I also believe I said, nothing I tried made any difference. That's complete failure. Thank you for the advice about the kernel parameter, but it did not change anything (i.e. total failure). Here is the lspci -vv snippet: Code:
00:02.0 VGA compatible controller: Intel Corporation N10 Family Integrated Graphics Controller (prog-if 00 [VGA controller]) I don't know if this is important or not, but I thought I would mention it. Thanks. |
Quote:
Edit: Oh, I see. Trying now. |
I tried Xbacklight, but whenever I give it any command except "-help" (I tried xbacklight -inc 40, xbacklight -get, xbacklight -dec 40), it says
Code:
Cannot open display "" |
The fact that /sys/class/backlight be empty can have several causes.
Maybe there is no interface in /sys for your laptop's backlight, or it lies elsewhere, or the relevant driver is not loaded. Anyhow it seems that you need that the kernel driver "samsung-laptop" be loaded to be able to change the brightness level. Check that it be loaded with the command: Code:
lsmod|grep samsung|grep laptop If not try to load the driver manually. As root: Code:
modprobe samsung-laptop If the driver was not loaded at first but you could load it manually then try changing the brightness level. In any case please report what you got. EDIT if after the "modprobe" command the error message says something like "this driver conflict with another one", probably you need to to set at boot time the acpi_backlight kernel parameter this way: "acpi_backlight=vendor". To do that, just reboot and when you see lilo's greeting screen, hit the Tab key and type the command like this before hitting enter: Code:
Linux acpi_backlight=vendor If that command was successful, to make that setting permanent you can add a line like this in the proper image section of /etc/lilo.conf (do that as root): Code:
append="acpi_backlight=vendor" Code:
lilo -t -v Code:
lilo |
I tried
Code:
lsmod|grep samsung|grep laptop Code:
root@darkstar:~# modprobe samsung-laptop |
As "modinfo samsung-laptop" says:
Code:
parm: force:Disable the DMI check and forces the driver to be loaded (bool) Try this as root then: Code:
modprobe samsung-laptop force |
Thank you. However, for some reason when I try that, it says invalid argument:
Code:
root@darkstar:~# modprobe samsung-laptop force |
try this syntax
Code:
modprobe -f samsung-laptop |
The command I gave you was probably wrong, sorry. Instead, try:
Code:
modprobe samsung-laptop force=1 |
Thank you, but unfortunately that line gave me the exact same error. :(
|
Maybe that is because the interface used by the kernel to talk to the BIOS, needed by samsung-laptop, is not present.
To check, post the output of following commands, typed as root: Code:
dmesg|grep SABI Code:
kernel: This computer does not support SABI But there seems to be a workaround, though, which is to send a command to the card through the PCI bus. On some Samsung models, for instance you could type as root: Code:
setpci -s 00:02.1 F4.B=FF "setpci -s" is the core command, the "-s" option being the method used to select the device ("man lspci" will tell you more) "00:02.1" is the device number "F4.B" should be the property of the device to be set (just a guess), here the brightness "FF" being the maximum brightness value (in hexadecimal notation) The brightness can vary from "00" to "FF" (0 to 255 in decimal notation) but be careful with the low values : if you set it to 00 the screen will be black! It is not sure that for a N145P model the device number be 00:02.1. To check, type: Code:
lspci|grepVGA |
Yay, it worked! Thank you so much for the clear instructions and explanation. Maybe you wouldn't mind answering just two more questions?
On my output of lspci, could you tell me what the difference is between "00:02.0 VGA compatible controller" and "00:02.1 Display controller?" (00.02.0 was the one I used.) Code:
root@darkstar:~# lspci Thanks again for your help! |
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