I have tried to reach out on the Gentoo forums first. This is my post on the topic with all of the relevant information: https://forums.gentoo.org/viewtopic-t-1102080.html
As you can see, nobody has responded yet. Seeing that, I decided to create a post on these forums, hoping for a different outcome.
I am running media-libs/mesa-19.2.0, which is the latest since the last time I updated the system, which was two days ago, and so I am no longer running -rc builds like in my post above. Since then, 19.2.1 became available, as evident here, but I wouldn’t hold my breath that it will solve my issue.
As I stated in my post above, it doesn’t make sense for GCC flags to end up somehow affecting Mesa in such a way that only one of the GPUs in my laptop is registered by it. With that said, I would not completely rule it out at this point, but I will save that for last, as I do not have much time to mess around with finding the flag(s) which have this affect if it really is due to the flags.
Now, here is a post related to an error I get from VLC when playing videos, but it the error occurs with Lutris in this post: [SOLVED] Ubuntu 18.04 Lutris, graphical errors on menu
My output is:
mesa: for the --simplifycfg-sink-common option: may only occur zero or one times!
mesa: for the --global-isel-abort option: may only occur zero or one times!
Given that that post was from last year and that it was from a binary-based distro, Ubuntu nonetheless, I am even more skeptical that my GCC flags are at fault. Here’s hoping that AMDGPU-PRO is not necessary.
Thank you all in advance!
Edit
clinfo has no issues recognizing my dedicated graphics card, so…
This is what I stumbled upon while looking for the side-note VLC issue, where I found out about clinfo. If only the VLC issue were an OpenCL one…
Edit two
vulkaninfo registers both GPUs as well. This seems to be an OpenGL issue… Great.
Edit three
Well, updating to 19.2.1 did not help. Just to clarify, I am using DRI_PRIME=1 to select the dedicated graphics card.