28/08/2019 16:39, Andrew Rybchenko: > On 8/28/19 2:26 PM, Jan Viktorin wrote: > > Andrew Rybchenko <arybche...@solarflare.com> wrote: > >> On 8/28/19 12:51 PM, Jan Viktorin wrote: > >>> Andrew Rybchenko <arybche...@solarflare.com> wrote: > >>>> From: Ivan Ilchenko <ivan.ilche...@oktetlabs.ru> > >>>> + * @return > >>>> + * - (0) if successful. > >>>> + * - (-ENOTSUP) if support for dev_infos_get() does not exist > >>>> for the device. > >>> I believe that allowing PMDs to return -ENOTSUP is not a good idea. > >>> At the moment, all PMDs provides this kind of information. It is not > >>> always very reliable piece of information but for me, it is a piece > >>> of gold I would not like to loose when configuring devices. > >>> > >>> I think it should be mandatory for all PMDs to provide this > >>> function. Another possible way, give a sane default contents of > >>> this structure. But, please, do not return -ENOTSUP. > >> I agree that dev_infos_get() callback should be mandatory, but > >> what the function should do if the callback is not provided? > > One way would be to fail to register a PMD without that callback. > > Such PMD driver would be simply wrong. This is what I mean by saying > > "mandatory" - the callback MUST be provided. > > Typically callbacks are set on probe and > rte_eth_dev_pci_generic_probe() and similar functions could > be updated to reject devices with missing dev_infos_get callback. > However, there is a secondary process cases where dev_infos_get > is not essential since control path may be unsupported in secondary > process. > > Anyway, I think it is a separate story. > > > DPDK could be so nice to provide a default callback named like > > default_dev_infos_get_when_you_are_incompetent_pmd_author() returning > > mostly zeros and some always "known metadata" like device pointer, > > driver_name, ... > > Thomas, Ferruh, what do you think?
I like the idea of making some functions mandatory. If we need to provide a default callback, why not. I'm also thinking we need to better enforce a standardization of basic features to be implemented. It would make DPDK more mature.
