Re: [dpdk-dev] [RFC PATCH v3 1/3] ethdev: support device reset and recovery events

[Thomas Monjalon <thomas@monjalon.net>]

30/09/2020 10:35, Kalesh Anakkur Purayil:
> On Wed, Sep 30, 2020 at 1:21 PM Thomas Monjalon <thomas@monjalon.net> wrote:
> > > From: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
> > >
> > > Adding support for device reset and recovery events in the
> > > rte_eth_event framework. FW error and FW reset conditions would be
> > > managed internally by PMD without needing application intervention.
> > > In such cases, PMD would need reset/recovery events to notify application
> > > that PMD is undergoing a reset.
> >
> > We already have this event:
> >
> >     RTE_ETH_EVENT_INTR_RESET,
> >             /**< reset interrupt event, sent to VF on PF reset */
> >
> > I don't know why "INTR" is in the name of this event,
> > and I think it does not need to be restricted to VF.
> > The application does not need to know whether the reset
> > is caused by the PF, the FW or the HW.
> > That's why I think you could share the same event.
> >
> 
> [Kalesh]: Yes. As you mentioned, this event is used for some other purpose.
> I did not want to break the existing usage/purpose of this event.
> For example, upon receiving the RTE_ETH_EVENT_INTR_RESET event OVS
> application invokes rte_eth_dev_reset() to reset the port.
> The aim here is to recover from the device error condition without the
> intervention of Applications. PMD itself will recover from the error using
> the protocol with FW.
> 
> >
> > > +       RTE_ETH_EVENT_RESET,    /**< port resetting from an error */
> > > +       RTE_ETH_EVENT_RECOVERED, /**< port recovered from an error */
> >
> > You ignored my previous comments:
> > "
> > What the application is supposed to do when receiving such event?
> > How the application knows that flow rules were resetted?
> > Is there any other configuration resetted?
> > These informations must be explicit in the doxygen comments.
> > "
> >
> [Kalesh]: Sorry, I missed it.
> I am not sure what you meant by "These information must be explicit in the
> doxygen comments ".
> Could you please elaborate a little how to/where to put these details?

/** is the start of a doxygen comment.
This is the place (in the .h file) to explain to application
developer what to do with the event.
The code + the comments is what we call "the API".

You should complete the description of RTE_ETH_EVENT_INTR_RESET
as well: the need for calling rte_eth_dev_reset() was not explicit.