Thank you for your enquiry. I will recommend to check with the manufacturer to ensure there is no compatibility problems with screen replacement.
Also I will recommend to ensure you are also running the latest BIOS and chipset drivers for the system.
Also have you try to change the brightness from display settings on windows with out using the buttons assign.
I have exactly the same problem with the T450, same panel.
Brightness buttons do not work, Brightness slider of Powermangement is missing.
Brightness can be adjust with the slider of the Intel 5500 Software.
Brightness can also be adjusted with the buttons, before windows is started.
I have the latest chipset drivers installed.
I installed many different versions of the display driver. Downloads From Intel, from Microsoft, from Lenevo. Non of them works.
Also the default Microsoft driver does not work.
What can I do?
Have you tried something like this?
- Go to Start Menu > Search and type "Device Manager" and then launch the Device Manager app
- Scroll down to the Display Adapters entry in the device list and expand the option. Right-click on the installed display drivers, and choose Update Driver Software from the context menu.
- In the ensuing interface menu, choose Browse my computer for driver software.
- Then choose the option "Let me pick from a list of drivers on my computer".
- In the next screen, select Microsoft Basic Display Adapter from the list under Show compatible hardware section. Then hit Next to continue.
- Windows should now install the selected driver and the display driver issue should no longer affect your screen brightness feature. You should now be able to increase or decrease display brightness.
For further reference
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yes I tried this solution, but it did not work for me. Brightness keys still without function.
I also tried different versions of the Intel driver and I tried different versions of Monitor INF files.
The Brightness slider of the Intel HD Software Tool works, but only does color adjustment and does not control the backlight brightness.
I tried different tools for windows to adjust the backlight brightness, some using the IOCTL_VIDEO_QUERY_DISPLAY_BRIGHTNESS Interface and some using the WmiMonitorBrightness Class. All of some don't work.
Using Linux, the xbrightness command is adjusting the brightness correctly, so I assume this is a windows driver problem and it is related to the power management.
Did change any hardware on your computer?
Could you please send us a screenshot of your Device manager, specifically draw down on Monitors?
Have you tried contacting your computer manufacturer about this matter?
we changed the display panel of the Lenovo T450 to the B140HAN01.2 (please read the first post of grosmar ^^)
My device manager shows the
Pnp Generic Monitor
Intel HD 5500 Driver in the newest version .4300.
Many people have the same problem, like this one: https://www.reddit.com/r/thinkpad/comments/3t3z1d/lenovo_t450_lcd_replacement_cant_change_brightness/
But it works perfectly running on Linux and also before Windows is started, even the brightness keys of the keyboard are working.
Please bear in mind that our graphics drive does not offer any brightness control feature. If you are unable to use Function keys after loading windows or loading Intel graphics driver, it might be that your computer model requires drivers directly from your computer manufacturer. Those drivers need to interact with the graphics V-BIOS and any power management settings your computer may offer.
you need to reinstall your old crappy panel
then u need ubuntu live on usb then u need a copy of ur crappy panel edid
sudo apt-get install read-edid
sudo get-edid > edidbackup.bin
find ur manufacturer and product id
reinstall good panel then use more complex process to write the manufacturer and product id to ur good panel