[dpdk-dev] [PATCH v4 1/3] lib/librte_ether: add support for port reset

[Zhao1, Wei]

Hi, Thomas

    All questions about this patch set has been answered, is it clear or not?And is there anything that I should do for it?
Or it is OK for merge into 17.02-RC2?

Thank you.

> -----Original Message-----
> From: Zhao1, Wei
> Sent: Friday, April 14, 2017 4:03 PM
> To: Thomas Monjalon <thomas.monjalon at 6wind.com>
> Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; Mcnamara, John
> <john.mcnamara at intel.com>; dev at dpdk.org; Lu, Wenzhuo
> <wenzhuo.lu at intel.com>
> Subject: RE: [dpdk-dev] [PATCH v4 1/3] lib/librte_ether: add support for port
> reset
> 
> Hi, Thomas
> 
> > -----Original Message-----
> > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> > Sent: Friday, April 14, 2017 2:31 PM
> > To: Zhao1, Wei <wei.zhao1 at intel.com>
> > Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; Mcnamara,
> John
> > <john.mcnamara at intel.com>; dev at dpdk.org; Lu, Wenzhuo
> > <wenzhuo.lu at intel.com>
> > Subject: Re: [dpdk-dev] [PATCH v4 1/3] lib/librte_ether: add support
> > for port reset
> >
> > 2017-04-14 01:29, Zhao1, Wei:
> > > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> > > > 2017-04-13 08:55, Zhao1, Wei:
> > > > > From: Ananyev, Konstantin
> > > > > > From: Zhao1, Wei
> > > > > > > From: Thomas Monjalon [mailto:thomas.monjalon at 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.
> >
> > Is it said somewhere in the doc that the configuration is lost when
> > stopping a device?
> > Can we say which configuration parameter is kept and which one is lost?
> >
> > rte_eth_dev_config_restore() is called in rte_eth_dev_start().
> 
> Port reset process not only involve the rte_eth_dev_start() and
> rte_eth_dev_stop().
> It also involve eth_dev_uninit() and eth_dev_init() process，
> in which PMD device uninit and init. In this case, for example, data-
> >mac_addrs buffer is freed so it need to add store and restore function.
> BUT, if you only call stop/configure/start process, that is not strictly what
> named "device reset".