GPU on Pi

Is it possible, from within RISC OS, to interrogate the GPU to ask it what resolution it is sending to the monitor and/or what resolution it thinks is the monitor’s preferred value?

As a newbie I’m probably completely misunderstanding your question, but OS_ScreenMode seems to put the current resolution into R1. The following correctly returns 1680 and 1050 for me:

SYS “OS_ScreenMode”, 1 TO , mode
PRINT mode!4
PRINT mode!8

No idea about getting the preferred resolution though!

That tells you what RISC OS is sending to the GPU.

The video works in a clever way on the Pi. RISC OS is set to a resolution which the GPU (usually) accepts. The GPU then, separately, decides what resolution the monitor prefers and up/down scales the picture accordingly. The monitor (if it is a LCD monitor) has a fixed native resolution in hardware and will, itself, up/down scale the picture it gets from the GPU if it is within its capability to do so.

I wasn’t kidding when I said that I’d probably misunderstood you :)

I see what you’re asking now but I don’t have a clue how to accomplish it.