16/03/2023 11:46, Ferruh Yigit:
> On 3/16/2023I 9:19 AM, Dmitry Kozlyuk wrote:
> > On Thu, Mar 16, 2023 at 4:11 AM fengchengwen <fengcheng...@huawei.com>
> > wrote:
> >> Because we have no API to know the PMD whether impl specific ops, we could
> >> only knowed by invoking.
> >> Except above impl, I also consider the other two:
> >> 1. just invoke rte_eth_dev_priv_dump without previous printf("Device
> >> private info") and later error printf.
> >> and I think people may curious about the extra output without a prompt
> >> just like "Device private info".
> >> 2. use fmemopen (the below code), this way will perfect process the PMD
> >> which not imp ops.
> >> FILE *f = fmemopen(buf, max-size(e.g. 128KB));
> >> ret = rte_eth_dev_priv_dump(port_id, f);
> >> if (ret == 0) {
> >> printf("Device private info:\n");
> >> printf("%s", buf);
> >> }
> >> But the windows platform don't support fmemopen.
> >>
> >> Hope for more feedback.
> >
> > What if rte_eth_dev_priv_dump() was a documented no-op when "f == NULL"?
> > This can be implemented in ethdev layer:
> > 1) if not implemented, return ENOTSUP
> > 2) if f == NULL, return 0
> > 3) else call PMD
> > Technically, even now a null device handle can be used, but this is
> > cumbersome and wastes resources for running the API twice.
>
>
> Not sure about to overload "f == NULL" condition to detect the feature
> support.
>
> It may be good to have a generic way to detect the support.
>
> One way is to add new set of APIs just to test the dev_ops, and return
> boolean like:
> 'bool rte_eth_dev_is_priv_dump(uint16_t port_id);'
>
>
> Another option can be introducing an enum, each enum item can represent
> a dev_ops and a single API can be used to detect the support. This
> requires more maintenance for long term, as app needs to know more,
> not sure if I like this.
>
>
> If there is no objection to add new APIs, I can own the task, to have
> APIs like:
> 'bool rte_eth_dev_is_xxx(uint16_t port_id);'
That's a debug function, so I don't think we need to know in advance
whether it will print something or not.
Returning ENOTSUP should be enough in my opinion.
