Re: How to commit a new architecture like RISC-V

[Helmut Grohne <helmut@subdivi.de>]

Hi,

On Thu, May 20, 2021 at 02:52:32PM +0800, zhangjialing wrote:
> the upstream is not support now , the patch is in our local repository.

I fear that this is a very bad basis to bootstrap Debian from. I
strongly recommend deferring a Debian port and upstreaming first.

If you want to proceed anyway, you'll pay a lot of maintenance cost.
You'll be maintaining a Debian derivative. You'll include your patches
and build it for a powerful existing architecture (most commonly amd64)
to cross bootstrap from. Then you can use the existing bootstrap
tooling (rebootstrap) and adapt it to use your derivative instead of
Debian.

So where does the maintenance cost come from? Debian is a moving target
and whenever it changes, you get to rebase your patches. rebootstrap
targets unstable. You'll be patching it. Either you'll be continuously
rebasing your rebootstrap fork or you'll be solving all of the generic
issues that I am solving yourself. Effectively, you'll be duplicating a
ton of work. Expect that it a full time employment just to keep in sync.
That's the overhead, not the development cost. Or you choose to not keep
in sync with Debian and then you'll have to effectively redo the whole
bootstrap once you start mainlining. Beyond this, you'll be unable to
use Debian infrastructure (e.g. jenkins.debian.net).

Or you may choose to go the significantly cheaper route and upstream
your patches now. Yes, it'll take time, but you're still faster that
way.

Helmut