Linux On My Samsung

Hi there!

First of all, thank you, voRia, for this forum and for samsung-tools!

I tried Linux Mint Debian Edition (XFCE). While it worked, attempting to change the backlight would make the display flicker and X would become unstable.

So, after discovering your Samsung PPA, I tried Samsung Tools and Easy Slow Down Manager with Xubuntu 11.04 on this laptop, no problems there. But I found XFCE a bit basic after using GNOME 2 for a long time, so I decided I'd try KDE. As I've found using Kubuntu to be a horrible experience, I installed Arch Linux with KDE.

Arch Linux uses Kernel 3.0, like LMDE, I think. While using KDE, I noticed that attempting to change the brightness would again make the backlight flicker and the laptop unstable. I found, using the Internet, that adding "acpi_osi=Linux acpi_backlight=vendor" to the kernel's cmdline would fix this problem; I could now turn down my backlight without any problems.

Kernel 3.0 has a samsung-laptop module that replaces the now discontinued easy-slow-down-manager and samsung-backlight module. I found, however, that samsung-tools still expects the esdm module to get some of its work done. I hacked samsung-tools to use samsung-laptop to get stuff done. This is a hack because I removed the ESDM code in the process...

Some observations:

• samsung-laptop's backlight code doesn't seem to let me blank the display (writing 0 to /sys/devices/platform/samsung/backlight/samsung/brightness just sets the screen to the lowest brightness) so I just force the use of vbetool, which does work
• The fan interface is pretty much the same, except that /sys/devices/platform/samsung/performance_level actually returns the fan's status as a word: "normal, silent, overclock" (yes, overclock replaces speed)
• Instead of ESDM's proc entry to disable Wi-Fi, rfkill is used instead. My R519 shows two devices when I "rfkill list wifi" (samsung-wifi and phy0); I block them both. While I can disable samsung-wifi only and stop the wireless, the Wi-Fi light remains on. I can disable phy0 only and the light will go off and the wifi will disable itself, but I'm not sure if samsung-wifi needs to be disabled as well...
• I use a subprocess hack to get the rfkill device index for samsung-wifi, but I found later that you can look in /sys/devices/platform/samsung/rfkill/rfkill0/...

I've attached a tarball with a slightly modified PKGBUILD and the patch. One thing I have noticed is that under Arch Linux, "rc.d stop samsung-tools" will not do anything - "python2 /usr/lib/samsung-tools/system-service.py" and "python2 /usr/lib/samsung-tools/session-service.py" are still present in ps's output.

Also, this laptop has a Celeron T3100. When attempting to load some cpufreq modules, I get the following:

[root@Arch ~]# uname -a
Linux Arch 3.0-pf #2 SMP PREEMPT Fri Sep 2 10:14:55 EEST 2011 x86_64 Celeron(R) Dual-Core CPU T3100 @ 1.90GHz GenuineIntel GNU/Linux
[root@Arch ~]# modprobe acpi-cpufreq
FATAL: Error inserting phc_intel (/lib/modules/3.0-pf/extra/phc-intel.ko): Input/output error
FATAL: Error inserting acpi_cpufreq (/lib/modules/3.0-pf/kernel/drivers/cpufreq/acpi-cpufreq.ko.gz): Input/output error
FATAL: Error running install command for acpi_cpufreq
[root@Arch ~]# modprobe p4-clockmod
FATAL: Error inserting p4_clockmod (/lib/modules/3.0-pf/kernel/drivers/cpufreq/p4-clockmod.ko.gz): Invalid argument

Is it a problem with the kernel, as http://aur.archlinux.org/packages.php?ID=24980 would suggest or does this Celeron really have no way of lowering its clock speed as pages on the Internet state? Thanks.

Hi,
thanks for your work and experimentation with 'Samsung Tools' and the 'samsung-laptop' kernel module. A lot of useful informations here!

Today I've installed a snapshot of the soon-to-be-released Kubuntu 11.10 and I've started to "play" with the new 'samsung-laptop' kernel module. Unfortunately, the first thing I've noticed is that it breaks the backlight control on my Samsung NC10.
The same happens also on other models, according to this bug report:

https://bugs.launchpad.net/ubuntu/+sour ... bug/810093

So, for now, I think the best viable option is yet to use 'samsung-backlight' and 'easy-slow-down-manager'.
As soon as the 'samsung-laptop' bug is fixed, I'll rewrite Samsung Tools to work with it.

Doobian wrote: samsung-laptop's backlight code doesn't seem to let me blank the display (writing 0 to /sys/devices/platform/samsung/backlight/samsung/brightness just sets the screen to the lowest brightness) so I just force the use of vbetool, which does work

On my NC10, I can blank the display by writing 1 to /sys/devices/platform/samsung/backlight/samsung/bl_power (0 to re-enable it).

Doobian wrote: One thing I have noticed is that under Arch Linux, "rc.d stop samsung-tools" will not do anything - "python2 /usr/lib/samsung-tools/system-service.py" and "python2 /usr/lib/samsung-tools/session-service.py" are still present in ps's output.

The rc.d script is not intended to start/stop the Samsung Tools services, its purpose is to set the initial status of devices at boot (and, as a consequence, it starts the system service). The session service is started when an user logs in and is stopped when the user logs out.

Doobian wrote: Also, this laptop has a Celeron T3100. When attempting to load some cpufreq modules, I get the following:

[root@Arch ~]# uname -a
Linux Arch 3.0-pf #2 SMP PREEMPT Fri Sep 2 10:14:55 EEST 2011 x86_64 Celeron(R) Dual-Core CPU T3100 @ 1.90GHz GenuineIntel GNU/Linux
[root@Arch ~]# modprobe acpi-cpufreq
FATAL: Error inserting phc_intel (/lib/modules/3.0-pf/extra/phc-intel.ko): Input/output error
FATAL: Error inserting acpi_cpufreq (/lib/modules/3.0-pf/kernel/drivers/cpufreq/acpi-cpufreq.ko.gz): Input/output error
FATAL: Error running install command for acpi_cpufreq
[root@Arch ~]# modprobe p4-clockmod
FATAL: Error inserting p4_clockmod (/lib/modules/3.0-pf/kernel/drivers/cpufreq/p4-clockmod.ko.gz): Invalid argument

Is it a problem with the kernel, as http://aur.archlinux.org/packages.php?ID=24980 would suggest or does this Celeron really have no way of lowering its clock speed as pages on the Internet state? Thanks.

I'm sorry but I can't help you here, I don't know if your CPU model is supported by PHC.
Try to ask on the linux-phc forum (http://www.linux-phc.org/), maybe someone there can help you.

voRia wrote:Hi,
Today I've installed a snapshot of the soon-to-be-released Kubuntu 11.10 and I've started to "play" with the new 'samsung-laptop' kernel module. Unfortunately, the first thing I've noticed is that it breaks the backlight control on my Samsung NC10.
The same happens also on other models, according to this bug report:

https://bugs.launchpad.net/ubuntu/+sour ... bug/810093

So, for now, I think the best viable option is yet to use 'samsung-backlight' and 'easy-slow-down-manager'.
As soon as the 'samsung-laptop' bug is fixed, I'll rewrite Samsung Tools to work with it.

Have you tried booting with "acpi_osi=Linux acpi_backlight=vendor" appended to your kernel cmdline? It solves the problem for me

For what it's worth, even with samsung-laptop blacklisted and samsung-backlight loaded, I still had the backlight problem under Linux 3.0 but YMMV.

voRia wrote: On my NC10, I can blank the display by writing 1 to /sys/devices/platform/samsung/backlight/samsung/bl_power (0 to re-enable it).

Ah, thank you! That works for me, too. I should've looked better...

voRia wrote: The rc.d script is not intended to start/stop the Samsung Tools services, its purpose is to set the initial status of devices at boot (and, as a consequence, it starts the system service). The session service is started when an user logs in and is stopped when the user logs out.

Ah, fair enough. I actually have no reason to stop Samsung Tools under normal use, it was just when I was playing with it that I needed to do so.

voRia wrote: I'm sorry but I can't help you here, I don't know if your CPU model is supported by PHC.
Try to ask on the linux-phc forum (http://www.linux-phc.org/), maybe someone there can help you.

Ah, thanks; will try there sometime. The BIOS has a power saving option depending on the state of the power adapter, maybe it does (somehow) do something.

I've just finished to rewrite Samsung Tools, and now it works with 'samsung-laptop' ('easy-slow-down-manager' support has been dropped). At the moment the code is available on the bazaar repository (https://launchpad.net/samsung-tools) and probably I will release it as version 2.0.

It seems to work pretty good, but I had to patch the 'samsung-laptop' kernel module to fix the backlight problems. I've also applied other patches that add support to other Samsung models.

I don't know if those patches will make their way in the official kernel in short times, anyway for Ubuntu users I've applied them in the kernel available on the PPA repository.