Bug 5794 - Add backlight control support for N150 and more
: Add backlight control support for N150 and more
Product: Desktop Bugs
Classification: ROSA Desktop
Component: Hardware
: unspecified
: All Linux
: Normal normal
: ---
Assigned To: Groups for solving hardware issues.
: Eugene Shatokhin
Depends on:
  Show dependency treegraph
Reported: 2015-06-18 18:53 MSD by Shalok Shalom
Modified: 2015-11-23 17:35 MSK (History)
0 users

See Also:
RPM Package: Samsung_Backlight_Control
Bad POT generating:

The requested data, logs, etc. (112.80 KB, text/plain)
2015-07-29 23:50 MSD, Eugene Shatokhin
X.org log from SuperX (20.27 KB, text/plain)
2015-07-31 00:09 MSD, Shalok Shalom

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Description Shalok Shalom 2015-06-18 18:53:06 MSD
This here work for me, can somebody create a packages, which copy that text file into that path, which get installed, when the Installer detect such a device ?


It seems to count for other Samsung Notebooks as well, does it hurt, if it get installed on each Samsung Laptop by default ?
Comment 1 Eugene Shatokhin 2015-06-18 20:14:51 MSD
First of all, before creating any packages, please do the following:

1. Check if booting with acpi_backlight=vendor kernel option helps.

2. It is worth looking at "Reporting Backlight Bugs" section in https://wiki.ubuntu.com/Kernel/Debugging/Backlight and checking what kind of backlight issue is yours.

3. Upload the data to us with hw-probe as usual. Twice:
* when the system booted without acpi_backlight=vendor
* when the system booted with acpi_backlight=vendor

Many backlight problems can be solved without additional packages.

By the way, different Samsung laptops may have different backlight interfaces, so it *may* hurt if a single solution is automatically applied during install.
Comment 2 Shalok Shalom 2015-06-19 00:34:44 MSD
I fix the issue on my netbook already, as stated.
Comment 3 Eugene Shatokhin 2015-06-19 16:57:36 MSD
(In reply to comment #2)
> I fix the issue on my netbook already, as stated.

Yes, I understand. However using that Xorg quirk for all Samsung laptops is error-prone.

If booting with 'acpi_backlight=vendor' helps, the problem can probably be fixed at the kernel level without the need for additional packages. 

There is already a number of laptop-specific settings of this kind in the kernel. It should be possible to add another one for Samsung N150 and, perhaps, send it to the mainline kernel too.

That is why it is important to check if 'acpi_backlight=vendor' helps.
Comment 4 Shalok Shalom 2015-06-19 20:49:51 MSD
Sorry for my harsh style, was already sleepy. :)

I will try that, in order to improve the things a bit.

Detect just right now, that it is possible to enable the brightness control in BIOS, it was set to auto, which means controlled by the AC plug in / or not.

Comment 5 Shalok Shalom 2015-06-20 12:29:51 MSD
Is this place in the line "linux" correct ? http://funkyimg.com/view/YnR3

If yes: It doesnt work. Here is the hw-probe: http://hw.rosalinux.ru/index.php?probe=9acd2bc7dc

Can i do something else ?
Comment 6 Shalok Shalom 2015-07-28 11:55:44 MSD
SuperX support Backlight on this device out of the box.
Comment 7 Eugene Shatokhin 2015-07-28 12:26:07 MSD
(In reply to comment #6)
> SuperX support Backlight on this device out of the box.

Too little information, unfortunately.

If changing backlight works in another Linux distro, we need more info, as usual, to compare with. Namely:

1) the version of that Linux distro

2) system log (after changing brightness back and forth): the output of 'journalctl -ab' if the system is systemd-based; otherwise - kern.log, system.log, the output of dmesg, or whatever

3) the list of kernel parameters (cat /proc/cmdline)

4) ls -l /sys/class/backlight

5) whether they use that or a similar quirk (https://wiki.archlinux.org/index.php/Samsung_N150#Backlight) or not, and if they use it - the contents of that file in /etc/X11/xorg.conf.d/.
Comment 8 Shalok Shalom 2015-07-29 22:08:16 MSD
Comment 9 Eugene Shatokhin 2015-07-29 23:50:32 MSD
Created attachment 4198 [details]
The requested data, logs, etc.

It is better to attach the logs and other requested data here (easier to search, etc.) rather than to pastebin. 

By the way, the screenshot you provided seems not to be for /etc/X11/xorg.conf.d/. Could you collect the output of 'ls -l /etc/X11/xorg.conf.d/' as root and post it here? Preferably, as plain text.
Comment 10 Shalok Shalom 2015-07-30 01:52:18 MSD
This here is the original folder in SuperX: http://funkyimg.com/view/ZAHv

I guess they use another name for the folder, which contains the data, that you mean, maybe this one here: http://funkyimg.com/view/ZAHw

superx@SuperX:~$ sudo ls -l /etc/X11/xorg.conf.d/
ls: cannot access /etc/X11/xorg.conf.d/: No such file or directory

PS: This screenshot in my previous comment result, since i copy the complete X11 folder from etc to my rosa installation, because i was without internet while i run this test, sitting in the park :)

That is, why this curious name in the path, if you mean that with 

' the screenshot you provided seems not to be for /etc/X11/xorg.conf.d/ '
Comment 11 Eugene Shatokhin 2015-07-30 12:35:35 MSD
(In reply to comment #10)
> This here is the original folder in SuperX: http://funkyimg.com/view/ZAHv

Well, it looks like they do not store X11 configs in /etc/X11 at all. They should have the X11 log though, /var/log/Xorg*.log. If so, please attach it here, as text.

2 more things you can try on ROSA:

1. Check if things go better with the kernel 4.1.x and the firmware files updated from http://abf-downloads.rosalinux.ru/spectre_personal/container/2523362/i586/main/release/

Please check both with and without acpi_backlight=vendor.

As usual, please upload the data using hw-probe after you try.

2. If (1) does not help, you can blacklist 'samsung_laptop' kernel module, as root:

echo 'blacklist samsung_laptop' > /etc/modprobe.d/blacklist-samsung.conf

Then reboot, see what happens and, again, use hw-probe.

'samsung_laptop' is responsible for one of the backlight schemes on your laptop but it may be faulty. If you blacklist it, I suppose, the system should resort to intel_backlight, which is more reliable.

If nothing of the above helps, well, the only option would be to keep that Xorg quirk (/etc/X11/xorg.conf.d/20-intel.conf) on that particular laptop.
Comment 12 Shalok Shalom 2015-07-30 13:09:19 MSD
What is the downside of this quirk, please ?
Comment 13 Shalok Shalom 2015-07-31 00:09:28 MSD
Created attachment 4199 [details]
X.org log from SuperX

Is it important, to switch the backlight, before open this file ?
Comment 14 Shalok Shalom 2015-07-31 00:28:32 MSD
Yep, it seems to be solved. I set the BIOS Setting back to the default blocking option and there is no intel file anymore here in my /usr/share/X11/xorg.conf.d/ while the backlight control work still. 4.1.2 with casual updates.

Thanks a lot :D
Comment 15 Shalok Shalom 2015-09-14 01:35:48 MSD
Sorry, i install a new R6 on this device and the backlight is again disabled by default.
Comment 16 Shalok Shalom 2015-11-23 17:35:38 MSK
Still the only way to enable backlight control here: https://wiki.archlinux.org/index.php/Samsung_N150_#Backlight