No HDMI output with Topfoison 2k display

Mark

Hello, I too have been experimenting with the TopFoison 2K display panel (with its HDMI board, so not directly via MIPI DSI) and the Firefly RK3399 board. No output either!

The TopFoison display panel is a portrait oriented display panel and reports itself as 1440x2560 (instead of 2560x1440, landscape). So each display line has 1440 pixels and it has 2560 lines (lets keep out the blanking information).

Is it possible to configure the RK3399 to output 1440x2560 over HDMI?
So far it seems not

Mark

Hi XCLR8,

according to the specification of the TopFoison 2k display panel, it has 2560 lines and each line has 1440 pixels. My PC nicely recognizes this as a "portrait" display (1440x2560). Of course, rotation function in Windows makes it possible to use it as a landscape oriented display.

If I look in the TRM document of the RK3399, there are two Video Output Processors (VOP_BIG, VOP_LITTLE). The VOP_BIG supports maximum output resolution of 4096x2160, VOP_LITTLE supports maximum resolution of 2560x1600. Consequently, the display requires more lines than the VOPs can deliver. For this reason, I can believe it will never work. I like to have this verified

However, would it be possible to have everything drawn 90 degrees rotated into the buffers? So internal buffers would require 2560x1440 buffers and just before going to the display (on the transmitter side, after the VOPs), rotate back. I don't know, I don't see any reference in the TRM that can do that.

Kind regards, Mark

Mark

So far I only found clues that indicate it will not work. I also can't find rotator-blocks that might circumvent the problem. And indeed, the documentation is very little. Custom resolutions are supported and modifications can be done, but you have to keep the maximum resolutions in mind that each HW-block has (in the chain to the display panel). As the image has to go thru the VOP and the HDMI transmitter, the VOP has a maximum on supported image size, which is smaller than required for the display (considering vertical direction then). I haven't found the maximum supported frame timings of the HDMI transmitter though.