Hey folks, I'm hoping for some advice on achieving decent graphics for my application. I've got a prototype running with a custom board hosting the NanoPi Neo Air and a bunch of my own hardware. The biggest issue right now is getting reasonable graphics performance. The difference between mainline and legacy support has had me confused and switching back and forth trying to find a useful solution. Here's what I've learned so far:
Mainline feels like the future, so that's my preference.
My application uses fbtft over SPI for the graphics. I achieved 72MHz SPI on mainline which gives almost reasonable performance. On legacy the SPI driver seems buggy and locks up after random intervals. It never worked at more than 32MHz or so... too slow for my screen. (this happened to me on Raspbian too)
So far my application is built on SDL2 which I now learn is not supported by fbdev. I would run X if there was an advantage... but it just feels like more layers unless I can use Mali to get some hardware acceleration.
I could port my app to SDL1.2 and use fbdev without X... but that feels like a backwards move also.
Not related to graphics, but mainline still has no i2s support on H3, which I need but apparently it's coming soon. Does this work reliably (slave mode) on legacy?
So I think the showstoppers for using the legacy kernel are:
Afraid of developing something new against an old kernel
Lack of understanding of FEX files, although maybe it's not so bad
SPI bug causing random lockup of the graphics... is there a known workaround for this problem?
If someone could point me in the right direction that would be great. I feel like I'm going around in circles. Thanks!
