I have new 4GB Rasberry Pi 4. I would like to mirror a touch screen,3.5 inch TFT LCD over 40 point connector and HDMI 1 over TV. I could not connect both and mirror together. Sorry I new to Rasberry pi.
Check out this page to see if your LCD is supported by
fbtft. If it is, find out its device name and try to set it up (yours looks like
sudo modprobe fbtft_device name=tinylcd35 # check if you have /dev/fb1. If so, try using it, e.g. # map a login console con2fbmap 1 1 # run X windows (remove xorg.conf if it refers to /dev/fb0) FRAMEBUFFER=/dev/fb1 startx # play a video sudo SDL_VIDEODRIVER=fbcon SDL_FBDEV=/dev/fb1 mplayer -vo sdl -framedrop test.mpg # view a picture fbi -d /dev/fb1 -T 1 -noverbose -a test.jpg
Framebuffer mirroring is described in the wiki, and involves installing a DMA driver and running
fbcp process while the mirroring is needed.
Unfortunately it seems that as of November, 2019, this cannot be done.
It can definitely multi-display using the same protocol/driver, however it can't do it if you are using DSI + HDMI.
The issue is that the underlying boot code enables a framebuffer to HDMI or a framebuffer for DSI, but not both.
There are TFT screens that actually have HDMI / mini HDMI input so you can have one of those as well as the TV