Display rotation moving forward

amolloy

Since display_rotate is deprecated, and display_hdmi_rotate & display_lcd_rotate only allow you to flip the display 180 degrees, it would be nice if there were an option to rotate Emulation Station and as many emulators as possible 90 degrees, preferably through a single setting in retropie_setup.sh (and I'm sure some folks would like a per-rom override, though that's not important for my particular use case).

For reference, I'm interested in this because I wish to use RetroPie with a Pimoroni HyperPixel 4, which is a portrait display. Thanks for listening, and keep up the good work!

mitu

Even if display_rotate is deprecated - the other parameters still have the same rotation options. I don't see a problem using a rotated display in the future on a Raspberry PI.

amolloy

Will RetroPie not use the VC4 FKMS V3D driver on Pi 4 when it is ready? According to the documentation for config.txt (https://www.raspberrypi.org/documentation/configuration/config-txt/video.md), those options can only flip the display, not rotate it 90 degrees when using the VC4 FKMS V3D driver (see under display_hdmi_rotate). This matches up with my experience, unless I've been doing something wrong (admittedly I am a bit new to this so that is definitely a possibility). Thanks.

mitu

Will RetroPie not use the VC4 FKMS V3D driver on Pi 4 when it is ready?

That driver is already been in use ever since the PI4 has been released and it works fine. The RetroPie support for PI4 relies on it working and being present - and it's working right now.

display_hdmi_rotate

I see now the mention about the FKMS driver not supporting this.
However, I think this functionality is still available, being implemented by the DRM subsystem. It might be configured differently - see this change.

amolloy

Thanks for the tip. I couldn't get things going with the info on that page, but it did provide me with some Google-fodder which led me to this page (which I don't know how I didn't find before): https://www.raspberrypi.org/documentation/hardware/display/

This led me to add the following to my cmdline.txt:

video=DSI-1:480x800,rotate=90

This looked promising initially, as the text console was rotated and oriented the way I wanted. Unfortunately, Emulation Station still comes up in the display's default portrait orientation.

The above page also links to the Linux framebuffer documentation here: https://github.com/raspberrypi/linux/blob/rpi-4.19.y/Documentation/fb/modedb.txt

I noticed in that documentation that it says the rotate option applies to the "initial framebuffer". I don't know if that makes a difference here.

I did notice that Emulation Station has a ScreenRotate option, and I was able to get it to be rotated the way I want. Unfortunately, so far anyways, the same cannot be said of any of the emulators I've tried.

Thanks again for the help! I'll keep working at it and see if I can come up with something.

mitu

@amolloy said in Display rotation moving forward:

This looked promising initially, as the text console was rotated and oriented the way I wanted. Unfortunately, Emulation Station still comes up in the display's default portrait orientation.

Then it means the rotation parameters are not used by the DRM system and 'transparently' working rotation isn't implemented.

I did notice that Emulation Station has a ScreenRotate option, and I was able to get it to be rotated the way I want. Unfortunately, so far anyways, the same cannot be said of any of the emulators I've tried.

RetroArch supports screen rotation, so any lr- emulators should work, see https://github.com/libretro/RetroArch/blob/b89663e213d97894879e2c51fc25b6426ca9ebf6/retroarch.cfg#L272-L284 for what needs to be changed in the retroarch.cfg to get it.

DuckMeFast

https://support.thepihut.com/hc/en-us/articles/115002072865-Official-touchscreen-is-upside-down

Solution for rasp4's

mitu

@duckmefast That only rotates the display 180 deg. - 90 or 270 deg. rotations are still not supported by the Pi4 via config.txt.