Re: [PATCH v1] rust: serdev: use Delta<Jiffy> for timeouts

["Gary Guo" <gary@garyguo.net>]

On Thu Oct 1, 2026 at 1:29 AM BST, FUJITA Tomonori wrote:
> On Wed, 30 Sep 2026 14:52:50 +0100
> "Gary Guo" <gary@garyguo.net> wrote:
>
>> I think the API should ideally use `Option<Delta<Jiffies>>` for this case, and
>> use `None` to represent indefinite wait.
>
> For read_poll_timeout(), where a timeout of 0 means "never time out"
> in C, we did not take Option for the timeout. Alice's comment [1]:
>
> | Another thing is the `timeout_delta` option. I would just have
> | written it as two methods, one that takes a timeout and one that
> | doesn't. That way, callers that don't need a timeout do not need to
> | handle timeout errors. (Do we have any users without a timeout? If
> | not, maybe just remove the Option.)
>
> serdev is in the same situation. Do we want an API that uses None for
> "never" here?

I don't like the "using 0" to mean forever, because 0 has a more sensible
meaning -- which is just do a poll and don't wait.

This one doesn't even return a result at all, so `Option` sounds reasonable.
Alternatively, just use `MAX_SCHEDULE_TIMEOUT` (i.e.
`Delta::from_jiffies(isize::MAX)`). We can perhaps add a `Delta::MAX` for this.

Best,
Gary