Does llvm have good riscv support for cross compiling? In my experience, even aarch64 isn't universally supported as a cross compiling target and building on embedded devices is an exercise in patience. I never even considered trying riscv chips in production since I assumed libs would be a hassle.

Even on rpi4, it's near impossible for a normal person to use the gpu because videocore6 is so locked down that you get zero lib support or documentation. And I'm pretty sure the only assembler is still from reverse engineering instead of the manfr.

The problem with the Chinese SBCs is lack of up-to-date LINUX support. Chip manufacturers are eager to provide Android support, but don't care a great deal about Linux support, which is, for them, a tiny niche market. Android will run on significantly out of date kernels, so the chip makers typically bump their kernels to the minimum Linux kernel version required to run a reasonable modern Android. Their Linux ports are based on Android kernels, so they lag significantly behind. And SBC manufacturers just use the kernels provided by the chipset manufacturer. The recent Orange Pi Rockwell-based SBCs, for example, shipped with a 4.x Linux kernel for their Linux port, at a point in time where Raspberry Pi OS was using a 6.x kernel.

Raspberry Pis do lag too, but they have significantly newer kernels, and are supported directly by several mainline distros.

I've chased a number of alternatives to Raspberry Pi in the interval where Rockwell SBCs were beating the pants off Pi 4s, only to find that they were shipping 4.x Linux kernels. My particular application uses USB audio devices, which don't really work prior to extensive rewrites of the USB audio stack in the 5.15 kernel. Raspberry Pi OS kernels are 6.1 or better. And Ubuntu on raspberry PI has later kernels than that (not sure which currently). Versions of Linux prior to 5.15 supported very old USB Audio 1.0 devices, but not currently available USB Audio 1.1 devices.

I imagine you would run into significant problems with video drivers being out of date on non-Pi devices as well. Raspberry Pi had to do their own Vulkan port, which seemed to require significant development effort.

I don't think that's likely to change soon. Rockwell doesn't really have a strong incentive to improve their kernel ports beyond what's necessary to support Android. And smaller SBC manufacturers aren't likely to have the resources to do a kernel port themselves.

You're not wrong.. but I also somehow doubt this is a dealbreaker. The reality is that nobody typically really cares about the kernel version they're running. It just rarely comes to bite you (like in your example). There are often vague security implications - but they always feel mostly theoretical

Furthermore if the platform is popular enough the community starts to step in. You can even see in the comments section of the previous link:

https://www.cnx-software.com/2024/02/08/licheerv-nano-low-co...

Some hobbyist went through the trouble to rebase their patches on top of a newer kernel version: https://github.com/sophgo/linux_5.10/pull/1

Furthermore, b/c unlike Broadcom/Rpi chips, these chips are widely available for commercial use - I'm gunna guess 3rd party companies are more likely to dedicate resources to maintain the software stack (even if the chip manufacturer is doing a crappy job of it)

I think this hits the nail on the head, especially longer term. It's hard to compete with this level of low-cost production with steadily improving specs. Raspberry Pi seems caught in the middle with getting more powerful and expensive in a market that wants either very powerful/expensive or good enough/supercheap. Even a pretty full "desktop" mini computer R7/32MB etc is down to $300 and change. If RAPI files for an IPO I'll be keen to see what kind of margins they are generating.

>> The real threat are new integrated chips from small Chinese companies that are coming down the pipeline - like the SG2002.

Exactly. Then there is more powerful Lichee Pi 4A (https://sipeed.com/licheepi4a) which directly competes with RPi4 and more powerful chips are in the making like P550 (https://www.sifive.com/boards/hifive-premier-p550).

I think it's the right time for IPO. RISC-V development is making huge progress fast. They are also upstreaming some changes. While SG200x is quite old and has unfinished Vector 0.7 extension, new chips claim to have vector 1.0. The documentation is still lacking but their progress is clearly visible.