W10 and XPS 14 (L421X) brightness

Essentially it's a bug with the Intel graphics drivers.

I just upgraded my own Dell L421x to Windows 10 and found two solutions, both of which are suboptimal. Pick one or the other - I went with #1 after finding #2 meant I couldn't get the Edge browser to start.

Workaround 1: Install very old Intel Graphics 4000 drivers: This gets you your brightness controls, but you will probably see some form of instability because the drivers are so old.

1. Browse to http://www.dell.com/support/home/us/en/19/product-support/product/xps-14-l421x/drivers 
6. 1. You do this by double-clicking on the EXE after it is downloaded, and clicking install. 
7. During the installation process, you will get a warning that you are overwriting the Intel display and audio drivers with older versions. Select the option to install anyway.
8. Wait for the install to be finished. DO NOT have anything that uses the video driver (games, videos) up while having the install.
9. The brightness should start working again after about the second or third time the screen flickers.

Workaround 2: Use Microsoft Basic Display Adapter This doesn't involve old software, but you end up losing a lot of multimedia options.

1. Open the Device Manager.
   1. You can do this by pressing Windows Key + X, then selecting Device Manager in the menu that appears near the start button. (Windows key is between Fn, and Alt assuming you have the same keyboard layout as me)
2. Expand the "Display Adapters" page.
3. Right-click the "Intel(R) HD Graphics 4000" item.
4. Click "Properties"
5. Select "Update driver".
6. Select "Browse my computer for driver software."
7. Select "Let me pick from a list of device drivers"
8. Select "Microsoft Basic Display Adapter"
9. Click "OK"
10. After the drivers switch over, you get the brightness controls back, but as mentioned you lose anything related to DirectX.

If you don't like either of these options, I did notice that the screen brightness ends up locked at the point when the broken Windows 10 Intel driver is installed. You can temporarily switch to the "Basic Display Adapter" to lower your brightness, and then reboot your computer. The brightness should be around the point where you rebooted your computer. e.g. If you set brightness to ~30% when the not-broken driver is installed, and then switch to the broken driver, your brightness will end up locked at 30% instead of 100%.

I know it's all ugly, so hopefully one of Intel or Dell gets the drivers fixed up.

Installed newest drivers from dell site - still brightness not working :(

@patrickceg thank for solution but it cant look like this. We pay and we want working!

@pejot I was able to get brightness to work after installing the Windows 8.1 driver (10.18.10.3262). The 3262 driver will work even if you have already installed the Windows 10 driver.

The file is called Video_Driver_VJH9H_WN_10.18.10.3262_A00.EXE

You can download it directly from this Dell link.

Its not working good. Getting messages about crashed drivers.

Same problem for me - I can't believe we have to deal with it! I don't want to choose between brightness and performance and I'm really unsatisfied for that!!! Does Intel knows about this, are they going to fix it?

Same problem here with my XPS 14:

- With Windows 10-Intel-Driver I can't change brightness

- Downgrade to Dell-Intel-Driver for Windows 8.1, I can change brightness again, but I always crashes after energy saving mode/ disabled screen

Beside, as soon as you downgrade a few minutes later Windows 10 automatically updates the driver. Only chance is to disable auto-updates for windows 10 - but than I get no updates at all anymore :-/

Dell, pls help with new drivers!

@Dennis2015, after Windows automatically upgrades the driver go to Device Manager, select Intel HD Graphics, right click and go to properties, then roll back the driver. It will roll back to the 8.1 driver and won't auro-update.

Hi Pejot,

I have uninstalled all the graphic driver and the video cards (both Intel and Nvidia), deleting them all, then I restarded the pc. Now on Device Manager I see Nvidia GT 630M and Base Windows graphic video, but everything works well. I hope....

Come on Dell, get your stuff together and make your product useable for us!

Intel HD Graphics 4000 and Windows 10 & Windows 8.1   ( Brightness fix with latest driver)

Brightness Fix with Driver Date 8/17/2015 )

Brightness problem Solved

Intel HD Graphics 4000 with NVIDIA® GeForce® GT650M graphics.

Install:

Intel HD Graphics 4000 Driver,     Driver Date: 8/17/2015

Driver Version: 10.18.10.4276

Make sure you backup your registry first before proceeding!!!!

open regedit  in  Run Command

Registry has wrong value:

Currently reads as :

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000] "FeatureTestControl"=

                                                                          "Edit DWORD 32 bit"=       f000

Registry with New Value:

You needed to change the value in registry to:  (   f008   )

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000] "FeatureTestControl"=

                                                                         "Edit DWORD 32 bit"=        f008

Then Restart Computer

Brightness Fixed with Latest driver.

Let me know if this was helpful to you

<ADMIN NOTE: Email id removed per privacy policy>

it worked until the latest W10 update ;(

it worked until the latest W10 update ;( any ideas for fixing it now?

@pokuba Are you using the batch file I attached previously? It has to be applied after every W10 update. I just updated to Insider Preview version 14931 and the batch file is still working for me.