Resolved: [Bug Report] Shin Megami Tensei - Persona 4 NTSC SLUS 21782

[Blyss Sarania]

[Bug Report] Shin Megami Tensei Persona 4 [NTSC-U]

# PCSX2 version: PCSX2 1.3.0 5, June, 2014 GIT
# CPU options: Tested Defaults and Extra modes
# Plugins used: Standard GSdx, SPU2x, lilypad
# Description:

When switching from hardware to software mode or vice versa, PCSX2 will crash about 25% of the time. I tested this thoroughly, with and without widescreen hacks, various settings, etc. Standard speedhacks enabled only(originally MTVU but also tried without).

It will also happen when using Pause/Resume from the system menu.

To cause the bug:

Boot Persona 4. Press F9 to switch from hardware to software. Repeat. Eventually it will crash.

I also tested it with other games and it seems limited to Persona 4. If you SPAM F9, it will crash in any game but I think that's to be expected. I confirmed it was unique to P4 by waiting 10 seconds between each press.

Edit: As noted down below, the bug does NOT happen when "Use Synchronized MTGS" is enabled.

[Nobbs66]

Could changing renderers be causing a syncing issue? Also try without any speedhacks at all including the recommended ones as well.

[Blyss Sarania]

Just tried with entire speedhacks panel disabled. Happened on 5th press of F9.

Code:

Overall 0 Widescreen hacks loaded
Loading patch 'DEDC3B71.pnach' from archive 'C:\Users\Blyss Sarania\Desktop\Emulation\PS2\cheats_ws.zip'
(Wide Screen Cheats DB) Patches Loaded: 57
Suspending single plugin: GS
    Saving GS
    Closing GS
Recovering single plugin: GS
    Opening GS
        Forced software switch enabled.
    Loading GS
Overall 0 Widescreen hacks loaded
Loading patch 'DEDC3B71.pnach' from archive 'C:\Users\Blyss Sarania\Desktop\Emulation\PS2\cheats_ws.zip'
(Wide Screen Cheats DB) Patches Loaded: 57
Suspending single plugin: GS
    Saving GS
    Closing GS
Recovering single plugin: GS
    Opening GS

[DESTRUIDOR]

An...Just not switch from hardware to software in the middle of the game.
Keep only with the best mode for you.

[Blyss Sarania]

BIG FIND:

It does not happen if you enable "Use Synchronized MTGS" in the GS tab!

So it is a desync issue of some kind I think!

[Nobbs66]

MTGS or Multi Threaded Graphics Synthesizer?

[Blyss Sarania]

I believe that's what it stands for yes.

[Nobbs66]

None of the acronyms in pcsx2 are hard to break apart. Like SPURS (SPU Runtime Environment) isn't easy to remember

[refraction]

Hmm can you try the last SVN build, I suspect it will be ok. There were sone changes made to MTGS soon after the swap

[Blyss Sarania]

So I tried the last SVN (r5927) and you are right, it does not happen. In fact completely spamming F9 doesn't break it, either. Recall in the first post I said spamming F9 crashed it in many games I tried. So it looks like there was a bug introduced in the MTGS changes, and it's not unique to Persona 4, but just worse and more apparent in it.