Re: [PATCH 2/2] ethdev: pre-emptively document rte_eth_dev_reset error code

[Luca Boccassi <bluca@debian.org>]

On Thu, 2017-10-19 at 15:53 +0100, Remy Horton wrote:
> On 19/10/2017 14:48, luca.boccassi@gmail.com wrote:
> > Document it immediately even if it's not yet supported, so that
> > users
> > and developers can already take into account about this use case,
> > and
> > thus avoid an API-incompatible change later on.
> 
> I'm not sure about documenting unimplemented features, as API docs
> ought 
> to describe what the code currently does. Then again reason seems OK
> and 
> I don't think there's hard guidelines on this..

Yeah I realised that, that's why it's a separate patch :-)

I'm just trying to avoid a foreseeable API breakage given we've been
using this API in production.

OTOH there are a few cases where perhaps EAGAIN is already a possible
error code to return - for example where the driver fails to
initialise? For example there's an error path that just returns -1 in
i40evf_dev_init

> > This is based on real-world production usage and customer
> > escalations,
> > using earlier patches from Intel.
> 
> Can you give the patchwork link for these patches?
> 
> 
> ..Remy

Based on these ones:

http://dpdk.org/dev/patchwork/patch/14009/
http://dpdk.org/dev/patchwork/patch/14011/
http://dpdk.org/dev/patchwork/patch/14010/

I had sent some feedback, as especially the ixgbe one was a blocking
call in case the PF was down, which is a deal breaker in most
situations given the API will be called from the controller thread in
most cases.

We've adapted and used these patches with the early rte_eth_dev_reset
for a year in production now, and we had a customer who requested it
since they were running into the problem it solves (PF flaps).

I have adapted them on the latest 17.11 tree and tested with X540
10gbit cards, and it seems to work as before. Should I send an RFC and
CC all of you?

Incidentally, are there specific reasons why the VF functionality was
dropped since the first patches were sent?

-- 
Kind regards,
Luca Boccassi