Hi Thomas, > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > Sent: Thursday, June 30, 2016 3:42 PM > To: Lu, Wenzhuo > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH v3] ethdev: fix DCB config issue on ixgbe > > 2016-06-30 01:40, Lu, Wenzhuo: > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Lu, Wenzhuo > > > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > > > > 2016-06-23 01:04, Lu, Wenzhuo: > > > > > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > > > > > > 2016-05-06 05:33, Wenzhuo Lu: > > > > > > > +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(). > > > > > > Second, I don't understand why having a function which > > > > > > configures the "multiqueue modes" without configuring properly > RSS/VMDq/DCB. > > > > > > 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.
> > > 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. > > That why I have to add a API to set the mq_mode before > rte_eth_dev_info_get. > > 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.