Actually you CAN emulate the PS2 on the Pi 4, but the speed is abysmal and the legwork required is insane. The tl;dr version of the story is you need to install Windows 10 using Windows on Raspberry and run PCSX2. SOME games run at playable speeds, but not many. Disgaea 1 and 2, Kingdom Hearts 1 and 2, Final Fantasy 10, and Final Fantasy 12 are playable. There are likely more, but those are the ones I've tested.
@offlercrocgod Xbox360 controllers do not have Bluetooth and will require a usb adapter to work. 3rd party adaptors are sold on Amazon and work just fine.
If you wanted to go the Bluetooth route, you need an Xbox one controller WITH BLUETOOTH. Not all have it. Or get a ps4 controller.
Now, it works for P1 in some games, but as P2 in other games.
Do you have any configuration overrides for the games where the configuration is not applied ? Try removing them. If that fails, give an example of such game and maybe provide a verbose log from running the game.
Given the timelines involved with designing and validating new hardware, especially when it involves chip design, we can be very certain that Pi 5 development is quite far along already. I know a Pi employee (jamesh, on the forums) mentioned already ~1 year before the Pi 4 was released that they had a good understanding of what the Pi 5 would be. I'd guess that at this point we're at most ~1.5 years from a Pi 5 release. I would hope to see it already this coming summer, but that may be a bit too optimistic.
Of course, the Pi 4 has still not peaked, since we're still waiting for Pi OS 64-bit, the full KMS video driver and Vulkan support. Personally, though, I believe the Pi 5 will in large part compatible with all the SW development work that's going on now, i.e. they will most likely keep the GPU very similar (at least from an architectural perspective).
It's pretty hard to speculate about what the Pi 5 will look like, but I mostly agree with @george-spiggott. Regarding using A75 cores, power consumption of the Pi 4 is already pretty much at the limit for what's practical when it comes to passive cooling. It's unlikely that they'd increase it further. This makes it challenging to provide a generational performance leap without going down to more dense manufacturing processes (such as 20nm or 16nm). So, I'd expect a process upgrade for the Pi 5. I also believe that at 16nm (and maybe also 20nm?) they will need to make some provisions to be able to keep the 3.3V I/O on the 40-pin header, since the silicon is not 3.3V tolerant. This will add cost and complexity.
My hope for the next Pi is that they're able to alleviate some bottlenecks in the design. It seems like memory bandwidth is lower than it should be, possibly because of internal bus limitations. My guess is that this is one of the reasons the performance of N64 emulation is still quite bad, despite seemingly not being particularly CPU or GPU limited on the Pi 4.
Plug in a Keyboard
While in Emulation Station press F4 to open the Terminal
sudo nano /etc/modprobe.d/xpad.conf
Change xpad triggers_to_buttons=1 to xpad triggers_to_buttons=0
Accept the changes.
Return back to Emulation Station by typing
(In my case, I noticed that the X-box controller had started acting strangely while in Emulation Station.
The D-pad buttons swapped positions in Emulation Station as they were previously in PPSSPP.)
Remap the controller in Emulation Station.
Remap the controller in PPSSPP if necessary.
(In my case, this was not needed.)
I'm not sure why this issue is affecting some people and not others.
Apparently, the problem is caused by the Trigger buttons somehow.
I'm having the same problem but one wireless redgear x-box gamepad is working fine and I'have configured all but my another gamepad which is detected but I cannot configure any buttons(wired redgear- x-box(in retropie game it is says x-box) but in windows it says ps3)... and I'm getting errors installing ps3 driver..
Any help will be appreciated!