FeatureTestControl registry value for Spectre 13-v001dx laptop

[MarkDbq]

After a recent Windows 10 update, the brightness keys on my HP Spectre 13-v011dx laptop stopped working. When this happened on my old Lenovo, it was because the update messed up this registry key:

HKLM\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000\FeatureTestControl

I changed the setting on the HP to try to fix it, but it didn't work. Now the problem is worse--when the computer wakes from sleep mode, the screen is completely dark with no backlight. I'd like to set FeatureTestControl back to its value before the Windows update, but I don't know what value to use. Could someone with the same model whose brightness keys still work please let me know their registry value?

Thanks!

[The_Fossette]

Hi @MarkDbq

Welcome to the HP Forums!

I reviewed your post and I understand that you are unable to  increase or decrease the brightness on the computer after the windows update.

I’d love to help!

The link below will provide you with the step-by-step instructions on how to perform a system recovery on your computer.

Step 1: Press Windows Key + R and type Regedit then hit enter.

Step 2: Press Ctrl + F and find FeatureTestControl. If your value is set to something f840 or f940 change it to ffff. To do this right click on “FeatureTestControl” and hit Modify then type in “ffff” on value data then hit OK.

Step 3: Then select HKEY_LOCAL_MACHINE > SYSTEM > ControlSet002 > Control > Class > {4d36e968-e325-11ce-bfc1-08002be10318} > 0001. On the right pane select again “FeatureTestControl” modify value data to “ffff” then hit OK.

Step 4: Then select HKEY_LOCAL_MACHINE > SYSTEM > Select make sure “Current” stays at 1.

Step 5: Restart your system and check whether the brightness is working now? 

Let me know how it goes and you have a good day ahead.

To simply say thanks, please click the "Thumbs Up" button to give me a Kudos to appreciate my efforts to help. If this helps, please mark this as “Accepted Solution”as it will help several others with the same issue to get it resolved without hassles.

Take care!

Cheers!

[MarkDbq]

HI,

Setting FeatureTestControl to ffff doesn't work. The brightness keys still don't work, and the backlight is off (screen is dark) after waking from sleep, requiring a hard boot to recover. I made sure all occurrences of FeatureTestControl were affected by the change, and I rebooted after the change.

If "ffff" is the proper setting, maybe the Windows update broke something else? Video driver for example? Are there other things to check, diagnostics to run, etc?

[The_Fossette]

Hi @MarkDbq

Thanks for the reply.

Follow the below steps.

1. Click START, right click on COMPUTER, and select MANAGE. 
2. Under Device Manager, select MONITOR, and right click on PnP Monitor. Uninstall and delete the drivers. 
3. At the top of the device manager, click the button scan for hardware changes.

After that check, if the issue is resolved.

Let me know how it goes and you have a good day ahead.

To simply say thanks, please click the "Thumbs Up" button to give me a Kudos to appreciate my efforts to help. If this helps, please mark this as “Accepted Solution” as it will help several others with the same issue to get it resolved without hassles.

Take care.

Cheers!

[MarkDbq]

Still no change.

In the Device Manager first I noted that the driver for the PnP Monitor was windows\system32\drivers\monitor.sys. Then I uninstalled the PnP Monitor in Device Manager, and from Windows Explorer I renamed monitor.sys to monitor.sys.old (I had to take ownership of the file to do this). Back in Device Manager I scanned for hardware changes, and since the file was renamed it said the driver was missing or corrupt. I picked Update Driver, and manually picked windows\inf\monitor.inf, which reinstalled the monitor.sys. I finished with a reboot. The brightness keys still don't work, and the monitor is dark after the computer wakes from sleep.

Perhaps some interesting additional information: If I open the action center (Windows+A) and click the brightness button, the value cycles through 100%-75%-50% etc., but the screen brightness doesn't change. Also, if I open All Settings and go to the "Customize your display page," changing the "Adjust brightness level" slider does nothing. The Apply/Cancel buttons beneath this control are disabled. It's as if the OS is completely disconnected from the hardware's brightness setting.

[The_Fossette]

Hi @MarkDbq

Thanks for the reply.

I recommend you to  perform recovery on the computer to put it back to the factory settings.

Follow the steps in the below link to perform the system recovery.

http://hp.care/2cf8noz

Let me know how it goes. Awaiting your reply!

Good day! Take care 🙂

Cheers!

[MarkDbq · Accepted solution]

Kind of drastic, but I didn't have much on the computer yet so I did the system recovery, which fixed the problem.

For the record, the FeaturetestControl setting ended up as f242. Maybe if I'd known and used that value, it would have fixed the problem.

[A4Apollo]

Hi @MarkDbq! 

I am happy to hear that your issue got resolved.

If you have any queries in future related to any HP products, you can always reach out to us.

We will try our best to help you out.

Take care,            

Have a great day!