On 8/26/25 10:38 PM, John Hubbard wrote:
On 8/25/25 5:47 AM, Danilo Krummrich wrote:
On Mon Aug 25, 2025 at 2:33 PM CEST, Alexandre Courbot wrote:
...
Naive question from someone with a device tree background and almost no
PCI experience: one consequence of using `From` here is that if I create
an non-registered Vendor value (e.g. `let vendor =
Vendor::from(0xf0f0)`), then do `vendor.as_raw()`, I won't get the value
passed initially but the one for `UNKNOWN`, e.g. `0xffff`. Are we ok
with this?
I think that's fine, since we shouldn't actually hit this. Drivers should only
ever use the pre-defined constants of Vendor; consequently the
Device::vendor_id() can't return UNKNOWN either.
So, I think the From impl is not ideal, since we can't limit its visibility. In
order to improve this, I suggest to use Vendor::new() directly in the macro, and
make Vendor::new() private. The same goes for Class, I guess.
Correction: when I went to implement this, I discovered that there is a better
way, which addresses both Alex's and your concerns.
The incremental diff below shows how. It provides:
a) .from_raw(), which in this case matches conventions slightly better
than new(). (I'm still learning that the Rust way is a bit different
that the C++ way! haha).
b) Only the parent module (in this case, that's pci:: ) can call
Class::from_raw(). This is exactly what we need. Fully private methods
wouldn't work, but leaving it open for any caller to construct a
Class item is also a problem.
Sorry, that's on me being not precise. When I said private I meant private to
the parent module.
The diff looks good, thanks!
Please also make sure to add #[inline] where appropriate and rebase onto
driver-core-next.
