Perfect, I think I know what's going on and also why it happens on Pi4 and not on Pi5.
Pi5 uses the rp1dsi output block which only has one plane so can't do hw-accelerated cursors so the cursor is always GPU-drawn. Whereas on Pi4 DSI can have a hardware accelerated cursor on a separate plane.
Until very recently whenever you used VNC or Pi Connect we would force the cursor to be GPU-drawn (rather than on a separate plane), then VNC would just capture the GPU-drawn screen with the cursor image included. If there's a rotation then that full image would be rotated, screen and cursor together.
But a recent feature is sending the cursor image separately so the VNC client draws the cursor itself. This means the Pi doesn't have to do GPU drawing work every time you move the mouse around, it just tells the VNC client where the mouse is and the VNC client draws the mouse cursor.
When the display is rotated and the cursor is on its own plane, the cursor image on that plane will be rotated. But when the VNC server sends the cursor image and location to the client, they aren't accounting for that image being rotated.
What's confusing is it seems a bit random when this vnc-client-drawn cursor is used. It never happens for me and I'm not sure why it's happening for you.
I shall summon our VNC / Pi Connect experts.
Pi5 uses the rp1dsi output block which only has one plane so can't do hw-accelerated cursors so the cursor is always GPU-drawn. Whereas on Pi4 DSI can have a hardware accelerated cursor on a separate plane.
Until very recently whenever you used VNC or Pi Connect we would force the cursor to be GPU-drawn (rather than on a separate plane), then VNC would just capture the GPU-drawn screen with the cursor image included. If there's a rotation then that full image would be rotated, screen and cursor together.
But a recent feature is sending the cursor image separately so the VNC client draws the cursor itself. This means the Pi doesn't have to do GPU drawing work every time you move the mouse around, it just tells the VNC client where the mouse is and the VNC client draws the mouse cursor.
When the display is rotated and the cursor is on its own plane, the cursor image on that plane will be rotated. But when the VNC server sends the cursor image and location to the client, they aren't accounting for that image being rotated.
What's confusing is it seems a bit random when this vnc-client-drawn cursor is used. It never happens for me and I'm not sure why it's happening for you.
I shall summon our VNC / Pi Connect experts.
Statistics: Posted by cillian64 — Wed Aug 20, 2025 3:16 pm