Brightness control issue on ThinkPad X220

[alehof]

Hello ThinkPad-Community,

I have a sporadic issue with the brightness control, thats mean sometimes I start my laptop from standby and the control with "Fn+Pos1 or FN+END" doesn't work.

There is no reaction and no on screen display progress bar. Also in the default Windows 7 energy settings is no control of the display brightness possible.

If the issue exist, only a complete reboot of the ThinkPad solve the issue.

I've also found some discussions about this in the internet but no solution helps realy.

NOTE: My Laptop has a complete clean install of Windows 7 and all drivers was installed by Lenovo System Updater.

Does anybody have the same issue?

Thanks for your help

[HiVolt]

This is an on & off issue that creeps up on various Thinkpads. It was very notorious on my X120e, but it doesn't happen on my X220 at all, and I sleep/resume it all the time...

It's a bug they can't seem to correct.

[alehof]

Hello HiVolt,
thanks for the feedback, it is possible that the issue only exist on machines with a own installation and not with the pre installed OS? What do you mean?

[HiVolt]

I have reinstalled my X220 with my own Win7 Pro discs (Machine came with Win7 Home) and I've updated all drivers like you, thru the System updater.

No issues with the brighness control or any other function key or OSD issue.

[alehof]

Thanks HiVolt,

one more question - do you have a WWAN module inside and which model?

Thanks for your assistance

[alehof]

The culprit was identified.

Wow, after a long research and troubleshooting, I've found the problem for the issue.

In my case is the WWAN device (Ericsson F5521gw) responsible for the issue.

Always after the brightness control issue, the WWAN device don't work correct. The WWAN was automaticly started but shows no reaction. Also a deactivate don't work (FN+F5).

I haven't a solution at the moment but the knowledge about the initiator helps me a lot.

A workaround for now: Disable the WWAN device in the BIOS, so I have done in my case. My ThinkPad works fine now without any issues.

Ok, perhaps has anyone a good idea for fixing the issue with the WWAN device.

Thanks

Sorry, my comment was too fast. Unfortunately the issue persist exist.

[HiVolt]

No, I don't have a WWAN card. The mSATA slot is empty in mine.

[alehof]

UPDATE

I haven't found the initiator for the issue until now.
But in my opinion is the WWAN card, Ericsson f5521 responsible for a part of the issue.

I have deactivated all Ericsson f5521 components in the device management (not BIOS) and now I have perhaps one error per week (prior to this minimum every day, sometimes also oftener).

But unfortunately the issue still exists.

Note: I use the standby mode of my thinkpad all the time (no shutdown)

Can anybody confirm my monitoring?

Does anybody have another idea?

Thanks for your feedback

[Puppy]

I don't have exactly the same issue but this one http://forums.lenovo.com/t5/ThinkVantage-Technologies/Bug-On-Screen-Display-level-indicators-sometim... might be related to it.

- it happens after restoration from hibernation only (reboot helps)

- I have f5521gw WWAN installed

[alehof]

New Update
Since my last posting and with deactivated WWAN (UMTS) module my system works fine.
I haven't a issue with brightness control since then.

Note: I allways use standby mode.