Hi, Thomas Monjalon > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monja...@6wind.com] > Sent: Thursday, April 13, 2017 6:07 PM > To: Zhao1, Wei <wei.zh...@intel.com> > Cc: Ananyev, Konstantin <konstantin.anan...@intel.com>; Mcnamara, John > <john.mcnam...@intel.com>; dev@dpdk.org; Lu, Wenzhuo > <wenzhuo...@intel.com> > Subject: Re: [dpdk-dev] [PATCH v4 1/3] lib/librte_ether: add support for port > reset > > 2017-04-13 08:55, Zhao1, Wei: > > From: Ananyev, Konstantin > > > From: Zhao1, Wei > > > > From: Thomas Monjalon [mailto:thomas.monja...@6wind.com] > > > > > 2017-04-06 02:57, Zhao1, Wei: > > > > > > > /** > > > > > > > > + * Reset an ethernet device when it's not working. One > > > > > > > > + scenario is, after PF > > > > > > > > + * port is down and up, the related VF port should be reset. > > > > > > > > + * The API will stop the port, clear the rx/tx queues, > > > > > > > > + re-setup the rx/tx > > > > > > > > + * queues, restart the port. > > > > > > > > > > > > > > s/The API/This function/ > > > > > > > > > > > > > > Please explain exactly the responsibility of this function, > > > > > > > and how it is different from calling stop/configure/start. > > > > > > > > > > > > In this reset feature, reset function can do the calling > > > > > > stop/configure/start process, but also It can also do some > > > > > > restore work for the port, for example, it can restore the > > > > > > added parameters of > > > > > vlan, mac_addrs, promisc_unicast_enabled falg and > > > > > promisc_multicast_enabled flag. > > > > > > Ok, but why start/stop can't do these things? > > > Konstantin > > > > This is because in i40e PMD code, start and stop process do not have > > the process of store and restore the added key parameters. Not only > > i40e but also other PMD code. So, in the function pointed to by dev_reset, > we add specific function do store and restore of some of the important > parameters listed above. > > Why store and restore cannot be implemented in start/stop functions?
Because reset and start/stop are used for two purposes, for example: Some user maybe just start/stop the port and he do not care what key parameters has been configuration last time, and even worse when he want to clear all the configuration last time , if we add specific function do store and restore in that two function, it is useless for them, and may cause a result that user do not expect.
