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T450 screen brightness - panel whitelist issue?

T430 and later, plus T530 and later series specific matters only
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stumpie92
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T450 screen brightness - panel whitelist issue?

#1 Post by stumpie92 » Mon Feb 17, 2020 6:56 am

I bought a refurbished T450 running Windows 10 and I can't change the screen brightness. Could it be that I have a screen not in the BIOS whitelist [2]?
Lenovo thinks [1] my machine was built using a 1366*768 display, it was sold to me as having a 1600*900, and it actually has 1920*1080 (FHD).
The screen type (from HWInfo64) is N140HGE-EAA. The BIOS/EDID whitelist [3] I found includes N140BGE-EA3 and N140FGE-EA2 but nothing else matching closely.
I don't fancy hacking the EEPROM(s) [5], though I have contacts who could probably do it. I did read [4] that the latest Intel graphics driver for W10 (15.40) doesn't check the whitelist, but I've so far failed to install it.
So
  • do I have the non-whitelisted screen problem?
  • if I get the non-Lenovoised driver installed, will all be cured or will I have to use a third-party brightness app?
Your assistance is solicited! It has taken me some weeks to get to this tentative diagnosis, so I will be most grateful for any help.

[1] type 20BUS23J19 not in PSREF, support.lenovo.com recognises it s/n PC05H19X
[2]http://forum.notebookreview.com/threads ... ax.774101/
[3] lost the link!
[4]https://forums.intel.com/s/question/0D5 ... 0&tstart=0
[5]https://old.reddit.com/r/thinkpad/comme ... whitelist/
( 355 - 600E - 770 - X20 - T40 - T41 - T60 ) T410 - T450
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Re: T450 screen brightness - panel whitelist issue?

#2 Post by BillMorrow » Thu Feb 27, 2020 7:13 pm

surely someone has something to contribute here..?
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She was not what you would call refined,
She was not what you would call unrefined,
She was the type of person who kept a parrot.
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Re: T450 screen brightness - panel whitelist issue?

#3 Post by JPOESQ » Thu Feb 27, 2020 8:15 pm

(Deleted) - See posts below discussing whitelist.
Last edited by JPOESQ on Fri Feb 28, 2020 9:00 am, edited 1 time in total.
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Re: T450 screen brightness - panel whitelist issue?

#4 Post by RealBlackStuff » Fri Feb 28, 2020 2:33 am

Obviously OP has a non-approved LCD.
T450 et al still has that effing screen whitelist, but do not despair: Tutorial: T450/T450s/W550s/T550/X250 Screen Whitelist Removal
Or mod the EDID (see "more" below).
List of whitelisted screens and more found here: viewtopic.php?t=126671
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Re: T450 screen brightness - panel whitelist issue?

#5 Post by iamdmc » Fri Feb 28, 2020 7:53 am

Yep whitelist strikes again

It's the reason I'm hunting for a broken T450s (with screen intact) 1600x900 or 1920x1080

I only realised too late that my pop's T450 was 1366x768 :(
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stumpie92
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Joined: Sun Feb 16, 2020 11:23 am
Location: Colchester, England

Re: T450 screen brightness - panel whitelist issue?

#6 Post by stumpie92 » Fri Mar 06, 2020 8:48 am

Thanks those above who gave me the right pointers and perhaps courage to hack the BIOS.
I'd still like to know why I can't get the newer Intel driver to work - after all Linux doesn't look at the whitelist!
Bruce
( 355 - 600E - 770 - X20 - T40 - T41 - T60 ) T410 - T450
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stumpie92
Posts: 5
Joined: Sun Feb 16, 2020 11:23 am
Location: Colchester, England

Re: T450 screen brightness - panel whitelist issue?

#7 Post by stumpie92 » Sat Jun 20, 2020 11:57 am

Oh well, just flashed the BIOS and all went according to plan but the machine is I believe bricked. On pressing the power button nothing happens at all. I will open it up and see if there is something clearly broken as well as verify the BIOS image with /u/aracer03 on reddit.
I do have some novice-assisting tips for how to do it all, but that can wait!
( 355 - 600E - 770 - X20 - T40 - T41 - T60 ) T410 - T450
(IBM indoctrinated) retirement addicted

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