Graphics Cards

[dust]

I'm using Radeon r290, Windows 10 64bit, Radeon Software Version 18.2.2, Adobe Lightroom Classic CC 7.2. Using Graphic Processor results in black screen in place of edited photo. It triggers after switching from library to develop module or randomly after some editing. Same thing is mentioned on Adobe forum PROBLEM:Black screen in Develop Module | Adobe Community but provided solution is to disable graphic processor... I did tried previous Radeon software version without any luck.

[arnie47]

I FOUND THE REASON FOR THS ISSUE!

After trying another video adapter from another PC which worked fine ona  WIndows 10 PC while also having the same issue on my main LR WIndows 7 PC I finally found what causes the problem:

when I use my GPU via DirectX everything works fine (also after change of libraries)

when I use OpenGL instead (e.g. by using the config.lua flag Develop.PreferOpenGL) the issue causes the black screen

The only problem is:When using Windows 7 there is always OpenGL used (as the newest DirectX version don't work with Win7).

When using Windows 10 I can selecht between DirectX and OpenGL.

I would be very pleased if you Adobe guys could try to reproduce this issue with the new information (switch to OpenGL by using the config.lua flag and change folder in Develop mode) to locate the bug.

[dust]

Good news!

How do I apply this? I have the lua file edited in notepad to

Develop.PreferOpenGL = false

and it is on Lightroom Settings folder but nothing happens - it is still using opengl.

[arnie47]

unfortunately I cannot tell you how to force LR to use DirectX!

The config.lua-Flag just gives you the possibility to prefer OpenGL, but I didn't find the possibility to do it the other way round. I asked in the LR forum but got no answer.

The only way I found out is an update to Windows 10 where DirectX seems to be preferred and therefore you can switch by using the config.lua file.

In WIndows 7 the OpenGL communication seems in any way to be preferred and therefore the flag has no consequence.

[dust]

I have Windows 10 and I have OpenGL by default...

[arnie47]

That's bad. I do not know what exactly makes LR select DirectX or OpenGL. Unfortunately the config.lua flag just works into one direction...