Re: [dpdk-dev] [PATCH v2 1/2] enic: determine max egress packet size and max MTU

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Jun 24, 2016 at 03:29:27PM -0700, John Daley wrote:
> Pull in common VNIC code which enables querying for max egress
> packet size with newer firmware via a device command. If the
> field is non-zero, it is the max egress packet size. If it is
> 0, the default value (9022) can safely be assumed. The value
> for 1300 series VICS using firmware versions >= 3.1.2 for blade
> series and >= 2.0.13 for rack series servers is 9208.
> 
> Tx buffers can be emitted only if they are less than the max egress
> packet size regardless of the MTU setting (the MTU is advisory).
> The max egress packet size can used to determine the upper limit
> of the MTU since the enic can also receive packets of size greater
> than max egress packet size. A max_mtu variable is added with
> a value of max egress packet size minus L2 header size.
> 
> The default MTU is set via the CIMC/UCSM management interface and
> currently allows value up to 9000. If the value is changed, the
> host must be reboot. To avoid the reboot and allow MTU values
> up to the max capability of the NIC, MTU update capability will
> be added with a max value capped by max_mtu.
> 
> Signed-off-by: John Daley <johndale@cisco.com>
> ---
> v2: Squished patch 1/4 and 2/4 into one. Tried to do a little
> better explanaiton of the intent of the patch in the commit
> message.
> 

Patchset applied to dpdk-next-net/rel_16_07

/Bruce