Re: [dpdk-dev] [PATCH v3] ether: use a default for max Rx frame size in configure()

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2017-04-07 16:18, Andriy Berestovskyy:
> Hey Bruce,
> 
> On 07.04.2017 14:29, Bruce Richardson wrote:
> > Is this entirely hidden from drivers? As I said previously, I believe
> > NICs using ixgbe/i40e etc. only use the frame size value when the jumbo
> > frame flag is set. That may lead to further inconsistent behaviour unless
> > all NICs are set up to behave as expected too.
> 
> You are right. If we take just Intel PMDs: some use the max_rx_pkt_len 
> only for jumbo frames (ixgbe), some always (i40) and some never (fm10k).
> 
> What if we add to the max_rx_pkt_len description: "the effective maximum 
> RX frame size depends on PMD, please refer the PMD guide for the details"?

I think the problem is not in the documentation but in the implementations
which should be more consistent.

> So with this patch we make rte_eth_dev_configure() clear and later PMDs 
> might change or clarify their limitations in the NIC guides.

If I understand well, the inconsistency between drivers was already an
issue before your patch.
Your patch fixes an inconsistency in ethdev without fixing the drivers.
We need to know if it is a good first step and if the drivers can be
fixed later.