05-19-2017 01:57 PM
I know this topic is a little bit old but I was wondering if any of you were able to use GPU acceleration after reinstalling the old driver designed for Windows 8.1
If I use the latest available Intenl driver I CAN use Photoshop GPU Acceleration features but can't control brightness. If I use the old Windows 8.1 video driver I can control brightness but Photoshop crashes and only works with GPU acceleration disabled...
10-03-2017 12:21 PM - edited 10-03-2017 12:23 PM
I use the latest drivers without much trouble... simply change one reg key and the screen brightness will work again.
Just paste that into notepad and save it as a '.reg' file eg P400fix.reg
Schedule it as a task or just click it after any major update.
10-05-2017 04:03 PM - last edited on 10-07-2017 07:39 AM by Bugbatter
All I’m saying is that some people will come on here clueless looking for an easy solution. This is why technical writers are paid well: easy instructions that people in secondary school can understand. I know what notepad is, but these big terms such as registers and schedulers will scare people away from your easy fix. Also, mention where it should/can be saved to.
10-07-2017 08:15 AM
I do not have this model so I cannot tell whether this fix will work. However, when working in the Windows Registry, it is prudent to make a backup as a precaution in case a mistake is made. One bad move can render a system inoperable.
Here are two ways to do this:
To use System Restore-
Create a restore point:
From the Start menu, type create a restore point.
Select Create a restore point from the search results.
Choose Create, and then follow the steps to create a restore point.
When you are finished making your changes to your system if you are not happy with them, restore from a restore point:
Select the Start button, type control panel and then choose that from the list of results.
Search Control Panel for Recovery.
Select Recovery > Open System Restore > Next.
Choose the restore point that was created before changes, and select Next > Finish.
As an alternative for a backup:
Manually Backing Up Windows 10
1. From the Start menu, type regedit.exe in the search box, and then press Enter. If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
2. In Registry Editor, locate and click the registry key or subkey that you want to back up.
3. Click File > Export.
4. In the Export Registry File dialog box, select the location to which you want to save the backup copy, and then type a name for the backup file in the File name field. (I ususally ask folks to save it to their Desktop.)
5. Click Save.
If you double-click on a reg.file it will restore everything you saved back to where it was, therefore, to Restore from a Manual Backup:
1. From the Start menu, type regedit.exe.
Press Enter. If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
2. In Registry Editor, click File > Import.
3. In the Import Registry File dialog box, select the location to which you saved the backup copy, select the backup file, and double-click on it or click Open. This will return your Windows Registry to its former state (before you made current changes).
I am not employed by Lenovo or Microsoft. I am a volunteer.
01-05-2019 08:33 AM - edited 01-05-2019 08:36 AM
I tried that, it doesn't work for me. Even after reboot.
01-20-2019 12:32 AM - edited 01-20-2019 12:34 AM
I noticed this issue the other day after dusting off my p400 and doing some updates...
I believe the new location of "FeatureTestControl" is 0001 instead of 0000
01-20-2019 06:28 AM
Thanks. I'll try again when it stops working again. I had reinstalled the driver a while back. I'm surprised it still runs very well with windows 10 with external monitor. Esp. After SSD upgrade.