HDMI Mode/Resolution Pi5

[Luke-Shepp]

I'm using a Pi5, with a waveshare 1600x600 display: https://www.waveshare.com/wiki/9.3inch_1600x600_LCD, and rendering an LVGL UI.

I'm having a problem where regardless of config.txt, cmdline.txt, or m_Screen (X, Y) options, the display reports 1920x1080 on the on-screen-display.

When using m_Screen(0, 0) I can render to the full physical screen but the UI is squashed vertically (these should be circle dials.):

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When using m_Screen(1600, 600) it only renders in the top left of the physical screen (most likely the top left 1600x600!)

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And the OSD always says:

I have tried many, many combinations of hdmi_group, hdmi_mode, framebuffer_width, framebuffer_height, hdmi_cvt, hdmi_timings, hdmi_ignore_edid, hdmi_edid_file with a custom EDID file. Also in cmdline.txt I have tried many combinations of different resolutions in video=HDMI-A-1:1600x600@60D.

Still to no avail.

If I output HDMI from my Macbook to the Waveshare display, I'm able to select 1600x600, the screen reports back 1600x600, and nothing is "squashed".

For some reason, no matter the setting, I cannot get the screen to size correctly from the pi5. It always shows 1920x1080 on the OSD and squashes my UI.

[rsta2]

This is the behavior of the firmware HDMI display support of the RPi 5 and Circle relies on the firmware for HDMI display support. Linux has its own HDMI display kernel mode driver for a while, which has more features, but this is not available for Circle. I tried to port it, but unfortunately I was not successful. It's too complicated. Most config.txt display settings are not supported on the RPi 5 and have no effect. video= in cmdline.txt also needs the Linux kernel driver to work. Unfortunately I cannot help here.

[Luke-Shepp]

No problem, I appreciate the response thank you.

The only solution I can think then, is to extend CDisplay (CScreenDevice?) and apply some scaling in SetPixel/SetArea to remove the "squash". I'll give that a go!

[rsta2]

You are welcome. You can use the class CWindowDisplay to use a portion of the HDMI display as a display (window). Please see sample/43-multiwindow for an example.