Amiberry v3.3+: How to make rotation_angle work? [solved]

Lolonois

There is a config switch for amiberry: rotation_angle but on my setup it does not rotate the amiberry display as stated in the documentation.

I am trying to rotate by 180 degrees (upside-down), but still get the display output as if with angle = 0 degrees.

Find here my amiberry.conf from /opt/retropie/configs/amiga/amiberry/conf/amiberry.conf, the rp500/rp1200.uae are stock/default. The games in questions do run without a separate/game specific *.uae file.

The vital stats:

Amiberry v3.3 compiled from source (NB: Effect can also be reproduced on Amiberry v4.1.2 source build)
Retropie-Setup Script 4.7.12 (cf1f3207), started from Retropie 4.7.1 image.
Rpi 4, 4GB
Display connected via HDMI+DVI adapter.

Anybody else encountered this? / can reproduce this?
Do I miss something?
Maybe @midwan you can chime in?

nemo93

hi @Lolonois! Thanks for reporting back and for providing details about your setup. Do you mind me asking first what game(s) are you testing with please? Share the full name including the extension (eg. awesome_game.lha). Second and out of curiosity what's the reason of you needing to rotate the screen? Do you have a special sceen?

Can you please test with the following settings set to no? So your amiberry.conf include the following:

default_horizontal_centering=no
default_vertical_centering=no

Also you're on pi4 hence do you rely on fKMS or KMS mode?

Lolonois

@nemo93 hello again.

Games tested (but I assume the effect is agnostic from a specific game): Pang_v2.2_0929.lha,AfterBurner_v1.4_Sega_0947.lha

I have set the both default_*_centering= to no but no change in result.

I am using FKMS (dtoverlay=vc4-fkms-v3d in /boot/config.txt).

Motivation: At some point in time Retropie will have to switch to Kernel 5.x (latest by Dec 2024), maybe the decision is made earlier to release a Kernel 5 based Retropie.

This means to use a more recent firmware/eeprom (rpi-eeprom-update).

In consequence the display_hdmi_rotate will no longer be supported. Which is bad for all hardware builds with a rotated display (90, 270 or 180 degrees). But there is a update path provided: With Kernel 5.x / recent rpi-firmware one can use in cmdline.txt something like ... video=HDMI-A-1:1600x1200@60,rotate=180. The retroarch encapsulated emulators and ports like VVVVVVV and yapesdl based games for example do work well and rotate as expected. I could speculate that before Dec 2024 amiberry has a retroarch integration and won't have to table this issue here.

However, amiberry does not honor the setting in cmdline.txt as replacement for display_hdmi_rotatein the config.txt. This is why I tried the amiberry.conf switch rotation_angle.
(other emulators reluctant to the cmdline.txt switch are linapple and jzintv, but that's a different story).

Currently I stick to Kernel 4.19 and the shipped rpi firmware of Retropie 4.7.1 (Firmware rev. 20200212) to be able to use inconfig.txt (display_rotate=2 / display_hdmi_rotate=2) since my display (stock LCD PC monitor) is built into the bartop 180 degrees "upside-down".

nemo93

@lolonois thank you very very much for such detailed response. Got it. I'll do some testing asap on my end as well. There are some upcoming changes to Amiberry so not easy but I'll see through it. Thanks again.

nemo93

@Lolonois I've had to ask @midwan and his answer was: "The rotation angle only works with SDL2, not dispmanx. Retropie uses the dispmanx version." If not mistaken we'll have to wait for the full KMS mode to be supported on pi4 to get support of that parameter. Sorry for not being able to assist further :(

Lolonois

@nemo93 NP, thanks for sorting this out. As stated earlier the whole testrun was anticipatory for the time when kernel 4.19 is discontinued. So still a few years development time for full KMS.