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2 Posts

10-11-2020

Canada

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Re:P1 Gen2 brightness control not working

2020-10-11, 18:05 PM

Actually I have a similar problem with my P1 2nd Gen...  but Although I have brightness settings that can be adjusted, my problem is the max level of the brightness.   When I power up the P1 on wall power, the screen brightness is not at the settings I prior power on set it at.. seems to be at a lower setting and I can not increase it to the setting I want.   Only after 5 mins, then the screen suddenly goes to the level I wanted in the first place.   I am 62 years old, but still doing software development and love my laptop. But my eyes have gotten weaker over the years and need the level I have set it at.   

 

so has any one notice that behavior with the P1 or X1 Series of laptops.   Power on brightness lower than it should be, but then restores to the proper brightness after 5 mins or so.

 

So for for now, I just live with it until it gets to the level I want in a few mins.

 

Richard

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1 Posts

10-27-2020

Canada

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  • Message 82 of 86

Re:P1 Gen2 brightness control not working

2020-10-27, 5:20 AM

I have exactly the same issue with my new P1 GEN 2 - OLD 4K Touch screen laptop which was bought in late September 2020. After searching and trying many approaches, I finally found the following approach is, IMHO, the best one to fix the brightness control issue. 

 

Thanks to other folks on other forums that posted / mentioned this approach.

 

The only thing you'll need to do is to change the values of two parameters in the computer's Registry. Below is the guide:

 

  • Open Registry: in windows search box, enter command regedit

 

  • Locate the following key
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}

 

  • Find the following Key / parameters and change the values

   1. LFP_Brightness_Control, The default value of this key is 0; Double click this key and input 1, press OK to save this value.

   2. LFP_NitRangeCount_30AE414100000000001D, The defaut value of my laptop is 201; Double click the key and input 257 in the inbox, press OK to save the value.

 

  • That's all the changes. Now you should see the values as displayed in the following screenshot.

 

  • Last step: Quit Registry and Restart your laptop; and good luck!
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1 Posts

10-29-2020

United States of America

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  • Message 83 of 86

Re:P1 Gen2 brightness control not working

2020-10-29, 0:54 AM

/its been a year since this posting and the brightness issue is still not fixed.

 

Is there any resolution on the horizon?

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1 Posts

11-25-2020

United Kingdom of Great Britain and Northern Ireland

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  • Message 84 of 86

Re:P1 Gen2 brightness control not working

2020-11-25, 16:20 PM

Thanks for the support and your reply! The registry edit instructions resolved the issue.

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2 Posts

12-10-2019

United Kingdom of Great Britain and Northern Ireland

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  • Message 85 of 86

Re:P1 Gen2 brightness control not working

2020-12-18, 20:16 PM
A recent windows update once again disabled the brightness control on my P1 gen2 and I can confirm this solution worked very well for me. Thank you.
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1 Posts

01-13-2021

United States of America

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  • Message 86 of 86

Re:P1 Gen2 brightness control not working

2021-01-13, 22:31 PM

Hi - Is anyone still having this problem? I have only had this laptop for 6 months and most posts are from 2019. Thanks!

 

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