From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [PATCH v4 1/3] lib/librte_ether: add support for
	port reset
Date: Thu, 13 Apr 2017 12:06:32 +0200
Message-ID: <4157272.TqMeIE0yWW@xps13>
References: <1490866456-52241-1-git-send-email-wei.zhao1@intel.com>
 <2601191342CEEE43887BDE71AB9772583FAE5871@IRSMSX109.ger.corp.intel.com>
 <A2573D2ACFCADC41BB3BE09C6DE313CA0207E89E@PGSMSX103.gar.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>, "Mcnamara,
 John" <john.mcnamara@intel.com>, dev@dpdk.org, "Lu,
 Wenzhuo" <wenzhuo.lu@intel.com>
To: "Zhao1, Wei" <wei.zhao1@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wr0-f180.google.com (mail-wr0-f180.google.com
 [209.85.128.180]) by dpdk.org (Postfix) with ESMTP id 8857B2C6E
 for <dev@dpdk.org>; Thu, 13 Apr 2017 12:06:34 +0200 (CEST)
Received: by mail-wr0-f180.google.com with SMTP id z109so32560648wrb.1
 for <dev@dpdk.org>; Thu, 13 Apr 2017 03:06:34 -0700 (PDT)
In-Reply-To: <A2573D2ACFCADC41BB3BE09C6DE313CA0207E89E@PGSMSX103.gar.corp.intel.com>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

2017-04-13 08:55, Zhao1, Wei:
> From: Ananyev, Konstantin
> > From: Zhao1, Wei
> > > From: Thomas Monjalon [mailto:thomas.monjalon@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?