[SOLVED] Problem with KMS on Samsung NC10

crom · 2010-02-11 20:47:48

Hi there,

I just upgraded and noticed that I must use KMS now. I disabled it previously because it renders my brightness-keys useless. Withoud KMS (kernel option 'nomodeset'), it worked well.

Any solutions/ideas?

Last edited by crom (2010-02-12 12:50:55)

panuh · 2010-02-11 21:06:19

See this thread: http://bbs.archlinux.org/viewtopic.php?id=90857

About your brightness keys. Maybe you will find a solution here: http://wiki.archlinux.org/index.php/Extra_Keyboard_Keys

I think you can write brightness values to the right place in /proc/ if i'm not wrong? Well you should first try if your keys are usable at all. About the commands for brightness I'm not sure...

Last edited by panuh (2010-02-11 21:06:58)

combuster · 2010-02-11 21:19:20

http://bugs.freedesktop.org/show_bug.cgi?id=20963

I thought that it is patched now, Greg issued a patch almost six months ago...

http://bugs.freedesktop.org/show_bug.cgi?id=20963#c72

Last edited by combuster (2010-02-11 21:21:01)

bdjnk · 2010-02-11 22:59:56

I've got the same issue as crom. I had i915.modset=0 in my boot parameters but now the latest version of the intel video driver (2.10.0) requires KMS (http://www.archlinux.org/news/484/). The result of running xbacklight is the notice that "No outputs have backlight property".

combuster · 2010-02-11 23:10:35

http://github.com/gregkh/samsung-backlight

Compile this driver and insmod it...

I wonder if it's merged in mainline...

Last edited by combuster (2010-02-11 23:11:07)

bdjnk · 2010-02-12 00:10:45

It is possible that I did something wrong, but I have done my compile and insmod to no change in the result of running xbacklight. The strange part is that when I first ran insmod samsung-backlight.ko the brightness dropped a bit.

Some additional information:
lsmod tells me that samsung-backlight is loaded and "Used by 0".
/var/log/messages.log tells me that "samsung_backlight: found laptop model 'NC10'"

crom · 2010-02-12 12:48:23

Thank you very much, combuster, this module works really well.

But I copied it to /lib/modules/`uname -r`/misc/ manually, ran depmod, modprobed it, added samsung-backlight to my modules-array in rc.conf and rebooted.

Now it works just well and i can tune it to my needs in the c-file.

I will mark this thread solved.

Last edited by crom (2010-02-12 12:51:09)

moose jaw · 2010-02-12 15:27:32

Can I follow up with a dumb question: what's the full procedure for compiling this module? I haven't been able to find good documentation on this on the wiki or via Googling, and have been striking out by simply cloning the git source linked to above and running "make" (make complains that there is no directory /lib/modules/2.6.32-ARCH/build, and even after manually creating this directory, it still won't work for me). Do you need to compile the whole kernel alongside the module as well? Is there supposed to be stuff in that 'build' directory that I am lacking? I'm sure there is something very basic I am missing here, but would be very grateful if someone could walk me through the steps (what is needed in advance, any specifics about the "make" command, make as root or as user, etc) so that I can get some backlight goodness on my NC10). Thanks.

crom · 2010-02-12 16:05:07

As normal user:
*Download the c-file and the makefile to any directory
*in that directory, just type make

the important result of this is a .ko file in your user directory, this needs to be copied to the module directory of the current kernel with root privileges, /lib/modules/`uname -r`/ as destination works also.

Run depmod as root afterwards.

Then you should be able to do `modprobe samsung-backlight` as root.

Edit: you need the kernel26-headers package and gcc for this.

Last edited by crom (2010-02-12 16:07:27)

bdjnk · 2010-02-12 19:35:52

Sure enough it works when I do it your way. Thanks combuster and crom.

knedlyk · 2010-02-13 00:08:01

Wow, impressive! Compiled, installed and it works. Only one issue remains - now I cannot use Fn keys to change brightness. Before upgrade and without KMS enabled it worked, but don't now.

Solved: added "N120" to the /usr/share/hal/fdi/information/10freedesktop/30-keymap-misc.fdi and restarted hal.

Last edited by knedlyk (2010-02-13 00:14:56)

moose jaw · 2010-02-13 01:04:49

Thanks crom for your help! My problem was simply that I was missing the kernel headers. (I thought I had them, but I forgot about the recent packaging switch to linux-api-headers.) Installed the module and it's working well.

One thing, though: has anyone else with an NC10 noticed that the xbacklight commands for increasing and decreasing brightness don't work very well with small intervals? I used to be able to do "xbacklight -inc 5" (or -dec 5) to adjust the brightness, but with this module now xbacklight doesn't respond to intervals under 10%, or sometimes 20%, depending on the current value. Plus, there is a fairly significant mismatch between the "-set" and "-get" values: after "xbacklight -set 50", "xbacklight -get" gives me a value of 42.857143; "xbacklight -set 40" then gives a -get value of 28.571429. Not the end of the world, obviously, but if anyone has an idea what's going on here, I'm all ears.

Or maybe there is some other interface that is preferable to xbacklight?

Last edited by moose jaw (2010-02-13 01:05:57)

moose jaw · 2010-02-13 01:22:43

Okay, to answer my own question: the module only supports 8 different brightness levels. This is documented in the c-file, I had just missed it before now. The increments correspond roughly to 15% intervals as available via xbacklight. On my machine, I've set Openbox to start up with xbacklight -set 30, and bound my brightness keys to xbacklight -inc/-dec 15, and all is well.

combuster · 2010-02-13 01:45:05

I'm happy it works for all of you, I just don't get it why this haven't been merged to mainline, but I'm sure that there is pretty good reason for that...

Arch Linux

#1 2010-02-11 20:47:48

[SOLVED] Problem with KMS on Samsung NC10

#2 2010-02-11 21:06:19

Re: [SOLVED] Problem with KMS on Samsung NC10

#3 2010-02-11 21:19:20

Re: [SOLVED] Problem with KMS on Samsung NC10

#4 2010-02-11 22:59:56

Re: [SOLVED] Problem with KMS on Samsung NC10

#5 2010-02-11 23:10:35

Re: [SOLVED] Problem with KMS on Samsung NC10

#6 2010-02-12 00:10:45

Re: [SOLVED] Problem with KMS on Samsung NC10

#7 2010-02-12 12:48:23

Re: [SOLVED] Problem with KMS on Samsung NC10

#8 2010-02-12 15:27:32

Re: [SOLVED] Problem with KMS on Samsung NC10

#9 2010-02-12 16:05:07

Re: [SOLVED] Problem with KMS on Samsung NC10

#10 2010-02-12 19:35:52

Re: [SOLVED] Problem with KMS on Samsung NC10

#11 2010-02-13 00:08:01

Re: [SOLVED] Problem with KMS on Samsung NC10

#12 2010-02-13 01:04:49

Re: [SOLVED] Problem with KMS on Samsung NC10

#13 2010-02-13 01:22:43

Re: [SOLVED] Problem with KMS on Samsung NC10

#14 2010-02-13 01:45:05

Re: [SOLVED] Problem with KMS on Samsung NC10

Board footer