Emulator

Forgot P2ME01 in that list, the Metroid Prime 2: Echoes bonus disc.

That P.ini shows up when pressing Show Defaults is not an issue that needs to be fixed. (It's unnecessarily complicated to fix - we would need to make some kind of list of either all TurboGrafx-16 games or all P bonus discs and make Dolphin handle games specially if the are/aren't on that list - and there's no real benefit to fixing it.)

If any GC discs with IDs starting with P don't have INIs that override the settings from P.ini, then that's a valid issue.

Err, I forgot it also would be possible to add a hardcoded check that skips one-letter INIs if the current game is a GC game. That's ugly, though.

The only disc I have to test this which tipped me off to the problem was the Double Dash bonus disc and it does apply the settings without an override.

https://i.gyazo.com/fdd018c1cee54261d4c1efd5ebaa6a5f.png GameINIs for PM4E01
https://i.gyazo.com/f7d550732607533afef0a55896dc97ce.png Safe Texture Cache being applied

Without knowing specifics, would it be possible to make a GameINI setting with the function of "ignore more general INI settings, only use the settings in this particular file or below"? So like in this example, you could put it in PM4xxx, and it would ignore all settings from PMxxxx, and Pxxxxx. Could maybe have use for specific region versions of games that need different settings than others; have the general settings in something like G41xxx, then the specific down in G41Jxx with the override. Just spitballing here.

We currently don't have a way to do that for all settings, but it's possible to do it for single settings as far as I know, so we can put a command in PM4.ini to ignore P.ini's SafeTextureCacheColorSamples value. Some affected discs already have that in their INI.

I can't find any references to the existence of PCKJ01 on the internet other than the Dolphin wiki, and it seems unreasonable that both PCKJ01 and PCSJ01 would be used for Japanese Pokémon Colosseum bonus discs. Does anyone know anything more about this game ID?

I'm suspecting that P4BJ08 is a typo too. The equivalents for other regions start with D4B.

PCKJ01 is another version of the colosseum bonus disc. Rather than trailers, it contains a demo for Pokemon Channel in it. You can identify the version by looking at the sleeve the disc is in more easily but the ID is (barely) visible here at least http://leafgreen.free.fr/celebi-bonus-disc.jpg

Here's the RE4 P4BJ08 disc too http://i.imgur.com/gSrhqaZ.png

Thanks for the info. I've added those two IDs to the PR.