Bug 653151 - Brightness controls don't work on Thinkpad T410
Summary: Brightness controls don't work on Thinkpad T410
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 14
Hardware: i686
OS: Linux
Target Milestone: ---
Assignee: John Feeney
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2010-11-14 17:47 UTC by Istvan Cebrian
Modified: 2013-01-10 07:32 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2011-08-31 17:05:30 UTC
Type: ---

Attachments (Terms of Use)
smoltSendProfile -p (7.96 KB, text/plain)
2010-11-14 17:47 UTC, Istvan Cebrian
no flags Details

System ID Private Priority Status Summary Last Updated
Red Hat Bugzilla 519105 0 low CLOSED Can no longer set laptop panel lcd brightness with 2.6.3x.x kernels 2021-02-22 00:41:40 UTC
Red Hat Bugzilla 588590 0 low CLOSED update breaks brightness on Thinkpad X100e 2021-02-22 00:41:40 UTC

Description Istvan Cebrian 2010-11-14 17:47:45 UTC
Created attachment 460390 [details]
smoltSendProfile -p

Description of problem:
Am running a fully updated version of Fedora 14 x86 ( on my Lenovo Thinkpad T410. Brightness controls either via keyboard or software don't work at all. Brightness is only dimmed when laptop is removed from AC power. When I plug it back in brightness is not restored and remains at a very low setting. Other FN+Key combinations work just fine.

The only way in which I can set brightness levels is by editing the file /sys/class/backlight/acpi_video0/brightness manually, so to set values I:

# echo 2 > /sys/class/backlight/acpi_video0/brightness (OR)
# echo 15 > /sys/class/backlight/acpi_video0/brightness 

I have tried using nvidia proprietary drivers but the problem is still present. In other distributions such as Linux Mint 10 problem was also present, however, it seemed that when I switched over to a console (using CTRL+ALT+F1) I could set the brightness there. In F12 when I switch over to a console and attempt setting the brightness I get a "^@" outputted and nothing happens.

Additional info:
# lspci -v
01:00.0 VGA compatible controller: nVidia Corporation GT218 [NVS 3100M] (rev a2) (prog-if 00 [VGA controller])
	Subsystem: Lenovo Device 2142
	Flags: bus master, fast devsel, latency 0, IRQ 16
	Memory at cc000000 (32-bit, non-prefetchable) [size=16M]
	Memory at d0000000 (64-bit, prefetchable) [size=256M]
	Memory at ce000000 (64-bit, prefetchable) [size=32M]
	I/O ports at 2000 [size=128]
	[virtual] Expansion ROM at cd000000 [disabled] [size=512K]
	Capabilities: [60] Power Management version 3
	Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
	Capabilities: [78] Express Endpoint, MSI 00
	Capabilities: [b4] Vendor Specific Information: Len=14 <?>
	Capabilities: [100] Virtual Channel
	Capabilities: [128] Power Budgeting <?>
	Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>
	Kernel driver in use: nouveau
	Kernel modules: nouveau, nvidiafb

# ll -R /sys/class/backlight/
total 0
lrwxrwxrwx 1 root root 0 Nov 14 16:40 acpi_video0 -> ../../devices/virtual/backlight/acpi_video0
lrwxrwxrwx 1 root root 0 Nov 14 16:40 nv_backlight -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/nv_backlight

# grub entry
title Fedora (
	root (hd0,0)
	kernel /vmlinuz- ro root=/dev/mapper/vg_iclaptop-lv_root rd_LVM_LV=vg_iclaptop/lv_root rd_LVM_LV=vg_iclaptop/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=pt-latin1 rhgb quiet
	initrd /initramfs-

# smoltSendProfile -p

Possibly related bugs: 519105 & 588590

Comment 1 Istvan Cebrian 2010-11-15 20:22:53 UTC
When I say F12 I meant F14.

Comment 2 Rolf Linder 2010-12-09 13:37:52 UTC
Same issue here.

It worked on F13, starting in F14 it stopped. You are unable to control brightness (video card Nvidia NVS 3100M in a Lenovo T410i).

this also includes, you are not able to use any auto-dim funcitons, since it will not restore to the original brightness once it has dimmed.

As reported on the thinkpadwiki-page it seems, that is issue is not known on the lenovo T41X systems with intel graphics (seems related to the nvidia systems)

Comment 3 Kyle McMartin 2010-12-09 16:22:48 UTC
Can you test the rawhide kernel, or the kernel from
http://repos.fedorapeople.org/repos/kyle/kernel/fedora-kernel.repo to see if it's fixed upstream in a newer release?

If so, we can then look at backporting it.


Comment 4 Istvan Cebrian 2010-12-11 17:10:31 UTC
Hi Kyle,

So i've added repo http://repos.fedorapeople.org/repos/kyle/kernel/fedora-15/i386/ and upgrade to kernel 2.6.37-0.rc5.git2.1.fc15.i686.PAE and brightness controls are working once again.

What can I do now?

Btw last kernel I was using was and brightness controls with this one still weren't working.


Comment 5 Kyle McMartin 2010-12-17 15:36:54 UTC
OK, good. I'll try to backport a fix for this next week, although, if its fixed in, we might get it 'for free' if I update F14...


regards, Kyle

Comment 6 Sean Carlos 2010-12-22 19:16:12 UTC
I have the same problem - brightness control function keys stopped working with the 2.6.35 series kernels, e.g.


(you can still change brightness in gnome power control tool or using 
/sys/class/backlight/acpi_video0/brightness as noted above)

They do work in a kernel taken from the above noted repo:


and they work if I go back to a F13 kernel, e.g. 


Laptop is a Sony Vaio FW series
VGA compatible controller: ATI Technologies Inc Mobility Radeon HD 3650

Comment 7 Kyle McMartin 2010-12-22 21:31:30 UTC
OK, thanks for testing. 2.6.37 will very quickly (I hope) make it to F-14/13, since it's seen quite a lot of positive testing (few 'unexpected' regressions as well)

In the meantime, any chance I could convince you to try:

Which is the last build of 2.6.36 I did in rawhide, so I can narrow down the changes and hopefully backport your fix to 2.6.35?

Comment 8 Sean Carlos 2010-12-22 22:14:34 UTC solves this problem in my case of a Sony Vaio - brightness up/down keys (Fn + F5 / F + F6) work like a charm.  Thanks, would love to see this in F14.

Comment 9 Istvan Cebrian 2010-12-23 23:36:28 UTC
Updated to problem however persists.

Comment 10 Josh Boyer 2011-08-31 17:05:30 UTC
At this point we're going to encourage people with this issue to update to fedora 15.  This won't be fixed for f14.

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