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What resolution(s) does the FPZ screen/drivers support? Weird problem with no display
#1
Hi, first off, this is entirely my fault for messing with settings. I wanted to try to enable shaders and in the process was seeing about setting different resolutions to see how they would affect performance/quality. I picked a random SNES game and pressed A to enter the setup menu. I went to the third option down to set resolution. I chose a 640x480 4:3 option (bottom half) and when I launched the game, I got the music but a black display. If I pressed Start + Select to exit, the music stopped but still black display. The only way to get out of it was to pull the battery.

So I went back and launched a different game without modifying anything and it worked. So I went back and looked at what settings it had (I think the third option down, 1280x720?). I then went to the game that I had messed with earlier and made it match the same resolution. When I launched it, the same thing happened. I did this with two other roms. It's like they are now "stuck" in a bad state. 

I know I shouldn't have modified anything but now that I have, how can I fix it? Is there a config or settings file per rom that I can open and compare (good vs bad) to try to "reset" things? What resolution(s) can the FPZ display support so I know I don't feed it a bad one?

Thanks.
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#2
I'll look into it in a bit to be more specific, but offhand, I'm thinking 2 things.

1) You shouldn't need to pull the battery. Holding the POWER button for 5-10 seconds should initiate a shutdown (unless it really froze up hard).
2) When you launch a ROM, you should be able to hold down the A button to bring up that menu. In there, I think there's an option to RESET all the settings that you applied to it previously.

I'll get some more specifics when I get a chance here.
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#3
I tried holding the power button 5-10 seconds to initiate safe shutdown but it didn't seem to work. I should have given it more of a chance (it's hard to tell what's happening with a black screen) Smile
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#4
Okay. After you reboot the system, you can go through the menu and launch that ROM again. Hit A repeatedly during launch to get the runcommand menu (which is that setup menu you mentioned) to come up.

Select "Remove video mode choice"
then select "Launch"

What happens when you select a different video mode (in that menu) is that it actually changes the HDMI output. If you had HDMI plugged in, you would likely see the monitor/TV change to that video mode. That is assuming that your TV can accept the mode you chose.

The problem with this (for the Freeplay Zero) is that the LCD is a clone of the HDMI, and switching modes dynamically drives it crazy. If you want to try forcing different video modes, you can do that in the /boot/config.txt file but it's not super straightforward.
Card Fighters' Clash 2 English Translation ( http://cfc2english.blogspot.com/ )
Neo Geo Pocket Flash Cart and Linker Project ( http://www.flashmasta.com/ )
Avatar art thanks to Trev-Mun ( http://trevmun.deviantart.com/ )
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#5
By the way, the Freeplay Zero is currently set to use

hdmi_group=2
hdmi_mode=16

Which maps to: 1024x768 60 Hz

You can see the 2 different groups and the modes they offer here:
https://elinux.org/RPiconfig

Also, it's worth noting that, if you boot up with HDMI attached, it will use the mode that the HDMI device (TV/monitor) recommends.
Card Fighters' Clash 2 English Translation ( http://cfc2english.blogspot.com/ )
Neo Geo Pocket Flash Cart and Linker Project ( http://www.flashmasta.com/ )
Avatar art thanks to Trev-Mun ( http://trevmun.deviantart.com/ )
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#6
Thanks for the info, this is really helpful. I will try to remove the video choice when I get home. I don't fully understand how video resolutions work in RetroPie / FPZ. The panel itself is limited to 320 x 240 right? But you are reading the data off HDMI and telling it to output to 1024x768? When it hits the FPZ screen, it downgrades to 320 x 240? Does this mean the system is "overworking" itself to output a higher resolution only to be downgraded when it hits the LCD? Or does it work differently?

Update: So I think your trick to remove/reset the resolution settings worked. I can play the SNES games again!
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#7
Good! I'm glad you got it fixed.

It's not actually "overworking" to output this higher resolution. In fact, it's a bit of a trick to use the LCD. The Pi doesn't really have native support for this type of LCD, so we can't just have all graphics processing done on the LCD. What we do instead is set up the HDMI and have all the graphics processing (using the GPU) happen there. At that level, the resolution doesn't really seem to affect the speed. Then, once the graphics are all rendered to HDMI, we make a quick copy down to 320x240. Here the size does matter, and if we wanted to do more than 320x240 it would likely be too slow for the hardware/software to keep up.
Card Fighters' Clash 2 English Translation ( http://cfc2english.blogspot.com/ )
Neo Geo Pocket Flash Cart and Linker Project ( http://www.flashmasta.com/ )
Avatar art thanks to Trev-Mun ( http://trevmun.deviantart.com/ )
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