RE: [PATCH v6 2/2] net/ixgbe: Fix SFP detection and linking on hotplug

[Jeff Daly <jeffd@silicom-usa.com>]

> -----Original Message-----
> From: Wang, Haiyue <haiyue.wang@intel.com>
> Sent: Tuesday, April 12, 2022 10:47 PM
> To: Jeff Daly <jeffd@silicom-usa.com>; dev@dpdk.org
> Cc: stable@dpdk.org; Stephen Douthit <stephend@silicom-usa.com>; Yang,
> Qiming <qiming.yang@intel.com>
> Subject: RE: [PATCH v6 2/2] net/ixgbe: Fix SFP detection and linking on
> hotplug
> 
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> 
> 
> > -----Original Message-----
> > From: Jeff Daly <jeffd@silicom-usa.com>
> > Sent: Wednesday, April 13, 2022 01:42
> > To: dev@dpdk.org
> > Cc: stable@dpdk.org; Stephen Douthit <stephend@silicom-usa.com>;
> Wang,
> > Haiyue <haiyue.wang@intel.com>
> > Subject: [PATCH v6 2/2] net/ixgbe: Fix SFP detection and linking on
> > hotplug
> >
> > Currently the ixgbe driver does not ID any SFP except for the first
> > one plugged in. This can lead to no-link, or incorrect speed conditions.
> >
> > For example:
> >
> > * If link is initially established with a 1G SFP, and later a 1G/10G
> > multispeed part is later installed, then the MAC link setup functions
> > are never called to change from 1000BASE-X to 10GBASE-R mode, and the
> > link stays running at the slower rate.
> >
> > * If link is initially established with a 1G SFP, and later a 10G only
> > module is later installed, no link is established, since we are still
> > trasnsmitting in 1000BASE-X mode to a 10GBASE-R only partner.
> >
> > Refactor the SFP ID/setup, and link setup code, to more closely match
> > the flow of the mainline kernel driver which does not have these
> > issues.  In that driver a service task runs periodically to handle
> > these operations based on bit flags that have been set (usually via
> > interrupt or userspace request), and then get cleared once the
> > requested subtask has been completed.
> >
> > Fixes: af75078fece ("first public release")
> > Cc: stable@dpdk.org
> >
> 
> So BIG change for new platform, DON'T CC to stable!
> 
> > Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
> > Signed-off-by: Jeff Daly <jeffd@silicom-usa.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 533
> > +++++++++++++++++++++++--------  drivers/net/ixgbe/ixgbe_ethdev.h |
> > 14 +-
> >  2 files changed, 410 insertions(+), 137 deletions(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> > b/drivers/net/ixgbe/ixgbe_ethdev.c
> > index f31bbb7895..9e720eee47 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -236,9 +236,6 @@ static int ixgbe_dev_interrupt_get_status(struct
> > rte_eth_dev *dev);  static int ixgbe_dev_interrupt_action(struct
> > rte_eth_dev *dev);  static void ixgbe_dev_interrupt_handler(void
> > *param);  static void ixgbe_dev_interrupt_delayed_handler(void
> > *param); -static void *ixgbe_dev_setup_link_thread_handler(void
> > *param); -static int ixgbe_dev_wait_setup_link_complete(struct
> rte_eth_dev *dev,
> > -                                           uint32_t timeout_ms);
> >
> 
> 
> > +     /* TODO - Even for platforms where ixgbe_check_sfp_cage() gives a
> clear
> > +      * status result, if there's no interrupts, or no interrupt for the SFP
> > +      * cage present pin, even if other interrupts exist, then we still need
> > +      * to poll here to set the flag.
> > +      */
> > +#ifndef RTE_EXEC_ENV_FREEBSD
> > +     struct rte_pci_device *pci_dev = RTE_ETH_DEV_TO_PCI(dev);
> > +     struct rte_intr_handle *intr_handle = pci_dev->intr_handle;
> > +     if (rte_intr_allow_others(intr_handle)) {
> > +             /* check if lsc interrupt is enabled */
> > +             if (dev->data->dev_conf.intr_conf.lsc)
> > +                     have_int = true;
> 
> 
> > +     /* Check for loss of SFP */
> > +     /* TODO - For platforms that don't have this flag, do we need to set
> > +      *  NEED_SFP_SETUP on LSC if we're a SFP platform?
> > +      */
> > +     if (hw->mac.type ==  ixgbe_mac_X550EM_a &&
> > +         (eicr & IXGBE_EICR_GPI_SDP0_X550EM_a))
> > +             intr->flags |= IXGBE_FLAG_NEED_SFP_SETUP;
> > +
> >       return 0;
> >  }
> 
> 
> TODO ?
> 

These were notes that some further refinements could be possible.  I can remove the comments if that makes it more acceptable.  The first TODO was a note that (for FreeBSD mostly) w/o interrupts the code below (not shown, which checks for 'have_int') will run vs. exiting early and relying on the NEED_SFP_SETUP flag being set elsewhere.  The 2nd TODO was a question from the original developer to himself where (I believe) he was considering other implementations which may not use MOD_ABS the same that other platforms do.  I don't think this is an issue (that I know of) so removing this commend and just moving on would be the best thing, and if someone else knows of a situation where this consideration might need to be made, then another patch can be submitted to address it.

> > --
> > 2.25.1