11-19-2018 02:54 PM
Laptop which is facing the problem, is Lenovo Z500.
A problem that is known, but I can not deal with it.
I installed 5 different drivers for the integrated graphics card, changed the parameter in the register FeatureTestControl parameter to FFFF, I installed various energy management. I changed the HD4000 driver to the basic one from Microsoft.
Nothing helps - when clicking the dash / dimming, a bar appears, which moves as it should, but the screen is still the same dark.
As I enter the settings -> screen, and there I set the slider, strange things happen, the screen goes self-darkening, dims itself, literally as if the laptop had a light intensity sensor ..
The BIOS can be used to light up the screen, it shines as it should, it does not get dark, etc. The matrix is okay.
Anyone have any suggestions on what you can do here?
Actually, for me, brightness can be 100% all the time, but the way with FFFF in the registry does not help.
11-19-2018 09:58 PM - last edited on 11-20-2018 07:21 AM by Andy_Lenovo
Welcome to the Community,
May we know how did you get Windows 10 in your laptop? Upon checking, the Lenovo Z500 is not compatible with Windows 10,
Expect that there will be compatibility issue if this is the case.
Admin note: link shortener converted to full URL for clarity
11-20-2018 07:34 AM
During boot you may quickly adjust the brightness. When bot Process is finished and contol passed to Windows, never again touch brightness up or down. This causes screen to almost darkness.
11-20-2018 09:16 AM
Hi! What's the default OS of your machine? We cannot provide Windows 10 drivers as it's not supported yet on this machine. Try to disable Adaptive Brightness. Go to > Power Options > Change plan settings > Change advanced power settings > Display > Disable Adaptive Brightness.
11-20-2018 03:43 PM
It would be best for us to bring the laptop back to it's original OS. This is one way for us to isolate the problem. Might as well download the drivers for Windows 8.1 once done, and observe for any changes,
01-30-2019 08:10 AM
I have had this probem since upgrading to Windows 10.
Lenovo say that this Model is not suited to Windows 10 but it can be made to work if you are prepared to iron out any issues.
The brightness control problem can be fixed by re-installing the original driver for the HD4000 graphics.
The original set-up is stored on the D drive ready for a restore.
To save time reloading the original driver, a shortcut can be set up on your desktop to the setup file.
This is the path, which should be the same if you have a Lenovo Ideapad Z500
Go through this install procedure every time Windows updates the video driver and part way through the install the brightness restores.
The above fix only lasts until Windows 10 decides to check for updates and automatically replaced the outdated HD4000 driver for the latest version. Unfortunately, neither Lenovo nor Intel seem to have any interest in fixing this bug in the current drivers.
So the problem comes back.
I had tried the Registry fix referred to other posts, changing the hex data for FeatureTest Control from "F000" to "FFFF". This didn't work for me.
However, just this week (Mon 28 Jan 2019) I read a similar post about a different Model of Lenovo laptop.
This user changed the hex data to "F008" and it had fixed the problem.
I tried this and it worked a treat (I have no idea what this does or why it works)
My Lenovo Z500 now has the latest version of Windows 10 with the latest version of the HD4000 video driver and the brightness control using Fn + F11/F12 works perfectly.
I have no idea whether this fix might fail with the next update of the video driver but at least its working now.
Take care when you change the registry.