Subject: Re: [net-next 02/16] i40e/i40evf: Rewrite logic for 8 descriptor per packet check

From: Jeff Kirsher <[email-masked]>
Date: Tue, 29 Mar 2016 22:29:24 -0700

On Tue, 2016-03-29 at 22:19 -0700, Alexander Duyck wrote:
> Minor correction here.  This is 72 hex, which is 114 in decimal.  The
> interesting bit I believe is the fact that we have both header and
> payload data in the same descriptor.
> 
> You should probably check with your hardware team on this but I have
> a
> working theory on the issue.  I'm thinking that because both header
> and payload are coming out of the same descriptor this must count as
> 2
> descriptors and not 1 when we compute the usage for the first
> descriptor.  As such I do probably need to start testing at frag 0
> because the first payload can actually come out of the header region
> if the first descriptor includes both payload and data.
> 
> I'll try to submit a patch for it tonight.  If you can test it
> tomorrow I would appreciate it.  Otherwise I will try setting up an
> environment to try and reproduce the issue tomorrow.

If you get it submitted tonight, I can have it ready in my tree for
testing for Jesse and the team when they get into the office tomorrow.