Hi Thomas,

-----Original Message-----
From: Lu, Wenzhuo
Sent: Thursday, June 30, 2016 4:23 PM
To: 'Thomas Monjalon'
Cc: dev@dpdk.org
Subject: RE: [dpdk-dev] [PATCH v3] ethdev: fix DCB config issue on ixgbe

Hi Thomas,

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-----Original Message-----
From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
Sent: Thursday, June 30, 2016 3:42 PM
To: Lu, Wenzhuo
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v3] ethdev: fix DCB config issue on
ixgbe

2016-06-30 01:40, Lu, Wenzhuo:

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From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Lu, Wenzhuo

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From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]

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2016-06-23 01:04, Lu, Wenzhuo:

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From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]

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2016-05-06 05:33, Wenzhuo Lu:

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+int
+rte_eth_dev_mq_mode_set(uint8_t port_id,
+			enum rte_eth_rx_mq_mode rx_mq_mode,
+			enum rte_eth_tx_mq_mode tx_mq_mode);

I've really tried to think about it and I think it is more or less a hack.
First, it is not explained in the doc when we should use
rte_eth_dev_mq_mode_set() instead of a simple call to

rte_eth_dev_configure().

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Second, I don't understand why having a function which
configures the "multiqueue modes" without configuring
properly

RSS/VMDq/DCB.

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Last, it is said that rte_eth_dev_configure() "must be
invoked first before any other function in the Ethernet API".

After checking the code, Honestly I'm confused. I don't find this description.

It's in the description of rte_eth_dev_configure():
	http://dpdk.org/browse/dpdk/tree/lib/librte_ether/rte_ethdev.h#n1904

The bad news is this rule is not followed. I think the reason is something has to
be done before configure.

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And on the contrary, I find rte_eth_dev_info_get is always called
before rte_eth_dev_configure. I believe it's the problem.
As rte_eth_dev_configure is not run, rte_eth_dev_info_get cannot get
the

right info.

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That why I have to add a API to set the mq_mode before

rte_eth_dev_info_get.

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Does that mean all the related examples are wrong? Any opinion? Thanks.

My opinion is that this area needs a good cleanup and easy API :)

OK. My solution is
1, Remove the description " rte_eth_dev_configure() must be invoked first
before any other function in the Ethernet API ". I think it's reasonable to execute
the rte_eth_dev_info_get before rte_eth_dev_configure, because we need to
get some NIC specific limitation to check if the configuration is right.
2, Add one more argument, " const struct rte_eth_conf *eth_conf ", for
rte_eth_dev_info_get, like this, void rte_eth_dev_info_get(uint8_t port_id,
struct rte_eth_dev_info *dev_info, const struct rte_eth_conf *eth_conf);
because getting the right info depends on the configuration.

And I'm a little lost, my patch has nothing to do with rte_eth_dev_configure. I just try to fix the issue that rte_eth_dev_info_get has dependency with configuration. If the configure is not right, we cannot get the right info.