04/10/2021 13:20, Ferruh Yigit: > On 9/27/2021 8:56 AM, Thomas Monjalon wrote: > > 27/09/2021 09:21, Wang, Jie1X: > >> From: Thomas Monjalon <tho...@monjalon.net> > >>> 26/09/2021 11:20, Jie Wang: > >>>> This patch adds a new API "rte_eth_dev_conf_info_get()" to help users > >>>> get device configuration info. > >>> [...] > >>>> + * Retrieve the configuration of an Ethernet device. > >>>> + * > >>>> + * @param port_id > >>>> + * The port identifier of the Ethernet device. > >>>> + * @param dev_conf_info > >>>> + * A pointer to a structure of type *rte_eth_conf* to be filled with > >>>> + * the configuration of the Ethernet device. > >>>> + * And the memory of the structure should be allocated by the caller. > >>>> + * @return > >>>> + * - (0) if successful. > >>>> + * - (-ENODEV) if *port_id* invalid. > >>>> + * - (-EINVAL) if bad parameter. > >>>> + */ > >>>> +__rte_experimental > >>>> +int rte_eth_dev_conf_info_get(uint16_t port_id, > >>>> + struct rte_eth_conf *dev_conf_info); > >>> > >>> It does not make sense to me. > >>> rte_eth_conf is passed by the app to rte_eth_dev_configure. > >>> Why the app would need to get the same info back? > >>> > >>> > >> > >> In rte_eth_dev_configure, dev->data->dev_conf copies the info from > >> port->dev_conf, and then the driver updates it. It doesn't same as > >> port->dev_conf. > >> We need to get the updated device configuration. > > > > OK I see. > > Please update the commit log to explain this. > > > > Also either an application needs to keep copy of the configuration (like > testpmd > does), or won't have any way to know device configuration details. > And for the apps that keeps the configuration, it has a risk that application > copy and device copy of the configuration diverged, as Jie mentioned. > > I think it makes sense to have a way to get the configuration from device, > small > applications can rely on it without keeping a copy of a config at all. > > And for testpmd, we have aligned with Xiaoyun to rely on the device > configuration more, in a way: > - When to display a config, use device copy as much as possible > - Use app copy of config to accumulate user config change requests to apply > them > later, sync app config with device config after config applied.
Makes sense, thanks.
