Emulator Issues #13032

Unrecoverable game freezes on Phantasy Star Online

Added by notaloop 18 days ago. Updated 1 day ago.

% Done:


Operating system:
Issue type:
Relates to usability:
Relates to performance:
Relates to maintainability:
Regression start:
Fixed in:


Game Name?

Phantasy Star Online I & II Plus

Game ID? (right click the game in the game list, Properties, Info tab)


MD5 Hash? (right click the game in the game list, Properties, Verify tab, Verify Integrity button)


What's the problem? Describe what went wrong.

When playing online the game will have an unrecoverable freeze, requiring a restart. Progress since the last save is lost.

What steps will reproduce the problem?

There isn't a consistent way of triggering them. Generally my frequency of freezing has been daily while keeping up with the latest dev version.

Is the issue present in the latest development version? For future reference, please also write down the version number of the latest development version.

17271 is the latest tested with instability.

Is the issue present in the latest stable version?

Latest stable version is 17245, 20+ hours of gameplay without freezing.

If the issue isn't present in the latest stable version, which is the first broken version? (You can find the first broken version by bisecting. Windows users can use the tool and anyone who is building Dolphin on their own can use git bisect.)

Somewhere between 17245 and 17271.

If your issue is a graphical issue, please attach screenshots and record a three frame fifolog of the issue if possible. Screenshots showing what it is supposed to look like from either console or older builds of Dolphin will help too. For more information on how to use the fifoplayer, please check here:

[Attach any fifologs if possible, write a description of fifologs and screenshots here to assist people unfamiliar with the game.]

What are your PC specifications? (CPU, GPU, Operating System, more)

Windows 10 Pro x64
Ryzen R5 3600
RTX 3060 Ti
512 GB SSD
Using GC adapter and GC controller

Is there anything else that can help developers narrow down the issue? (e.g. logs, screenshots,
configuration files, savefiles, savestates)

These freezes are usually suspected of being caused by network changes. PRs 10985/10920 may have changed network behavior in a way that increases freeze frequency. If back-to-back testing w/logging is possible, that might help confirm these PR are impacting network behavior on PSO.
Alternatively, re-testing 17271 but w/o those two PRs.


#1 Updated by JMC4789 18 days ago

If you're the one who can reproduce the issue, bisect it to an exact build. Asking devs who have never played the game to go after a bug that takes an indeterminate amount of time is a good way to get the issue back burnered. If we have an exact build where the issue started, we can potentially provide more information on what to do and ways to debug it.

#2 Updated by pokechu22 18 days ago

Also, are you using single core or dual core?

#3 Updated by AdmiralCurtiss 18 days ago

If you can get a process dump of Dolphin in the frozen state (Task Manager -> Details -> Dolphin.exe -> Create dump file), that is also likely to be helpful.

e: Wait, is the emulated game freezing, or the whole Dolphin process? If it's just the emulated game that might not be too useful...

#4 Updated by JMC4789 18 days ago

Based on what I remember from the early HLE BBA testing, this is the emulated game freezing.

#5 Updated by AdmiralCurtiss 18 days ago

If it's the emulated game freezing a savestate may be useful?

#6 Updated by notaloop 18 days ago

I can try getting a dump file and save state during a freeze. Bisecting will continue, I narrowed down to ~11 PRs or so.

#7 Updated by JMC4789 18 days ago

Great :)

If it is one of the more complicated BBA HLE pull requests, it's possible we can narrow it down to the exact commit through compiling the individual commits of the pull request too.

#8 Updated by notaloop 18 days ago

Using single core

#9 Updated by notaloop 11 days ago

Got a freeze on 17260, process dump is here:

Was unable to get a save state or FIFO, this crashed the entire emulator.

Will try 17253 next.

#10 Updated by notaloop 1 day ago

I'll start testing PR 11083 to confirm it fixes the bug. I'm not sure further bisection will be productive.

From my bisection testing:
17245 (20 hrs) and 17253 (27 hrs) appear stable.
17260 (15 hrs) and 17271 (10 hrs) have produced freezes.

The two builds in between 17253 and 17260 don't seem like they changed something that would cause this sporatic freezing issue.

#11 Updated by AdmiralCurtiss 1 day ago

Well it's impossible to prove that a sporadic bug doesn't exist in any given revision, you can only prove that it does exist. So I'm guessing that 17253 has the bug and you just got lucky, and that the bug was introduced in either 17249 or 17251 (because those builds touch network code).

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