GPU index option is ignored unless primary monitor is on preferred GPU

Is there an existing issue for this?

• This is a bug in RetroArch frontend
• I have searched the existing issues

Description

Any core using the GPU for rendering will use the GPU of the primary monitor.

Expected behavior

A core using the GPU for rendering should use the preferred GPU regardless of the primary monitor.

Steps to reproduce the bug

I have two cards in my machine. The primary card is an RTX 3080. The second card is an HD 5450 (for use with CRTEmudriver). I have a CRT TV connected to the 5450 through the VGA.

The only way I can ensure that cores which are GPU-dependent (such as LRPS2) run properly is by maintaining my primary monitor on the RTX 3080 and forcing RetroArch to run on a secondary display. I'm unable to shift my monitor layout so that the CRT is the only active display, or else the GPU index option will be ignored and processing will still be done on the HD 5450, which is not adequate to run such cores.

Version/Commit

1.20.0

Bisect Results

No

Present in the nightly version

I don't know

Platform & operating system

Windows 10 22H2

Affected Cores

affects all cores, but most obvious results are with LRPS2

Environment information

affects vulcan and directx

Relevant log output

No source file or test is identified. Trace RetroArch's GPU index option and display-selection behavior for Vulkan and DirectX on Windows, using the two-GPU setup described and LRPS2 as the first affected core to check. Done means the selected GPU is used regardless of which monitor is primary.