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From:   Oded Gabbay <oded.gabbay@gmail.com>
Date:   Thu, 10 Sep 2020 23:17:59 +0300
Message-ID: <CAFCwf10XdCDhLeyiArc29PAJ_7=BGpdiUvFRotvFHieiaRn=aA@mail.gmail.com>
Subject: Re: [PATCH 12/15] habanalabs/gaudi: add debugfs entries for the NIC
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     "Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
        netdev@vger.kernel.org, SW_Drivers <SW_Drivers@habana.ai>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "David S. Miller" <davem@davemloft.net>,
        Omer Shpigelman <oshpigelman@habana.ai>
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On Thu, Sep 10, 2020 at 11:16 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 10 Sep 2020 23:10:47 +0300 Oded Gabbay wrote:
> > On Thu, Sep 10, 2020 at 11:01 PM Jakub Kicinski <kuba@kernel.org> wrote:
> > >
> > > On Thu, 10 Sep 2020 19:11:23 +0300 Oded Gabbay wrote:
> > > > From: Omer Shpigelman <oshpigelman@habana.ai>
> > > >
> > > > Add several debugfs entries to help us debug the NIC engines and ports and
> > > > also the communication layer of the DL training application that use them.
> > > >
> > > > There are eight new entries. Detailed description is in the documentation
> > > > file but here is a summary:
> > > >
> > > > - nic_mac_loopback: enable mac loopback mode per port
> > > > - nic_ports_status: print physical connection status per port
> > > > - nic_pcs_fail_time_frame: configure windows size for measuring pcs
> > > >                            failures
> > > > - nic_pcs_fail_threshold: configure pcs failures threshold for
> > > >                           reconfiguring the link
> > > > - nic_pam4_tx_taps: configure PAM4 TX taps
> > > > - nic_polarity: configure polarity for NIC port lanes
> > > > - nic_check_link: configure whether to check the PCS link periodically
> > > > - nic_phy_auto_neg_lpbk: enable PHY auto-negotiation loopback
> > > >
> > > > Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
> > > > Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
> > > > Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
> > >
> > > debugfs configuration interfaces are not acceptable in netdev.
> >
> > no problem, but can we have only these two entries:
> > > - nic_mac_loopback: enable mac loopback mode per port
> > > - nic_ports_status: print physical connection status per port
> >
> > nic_ports_status is print only (not configuration).
>
> Doesn't seem like this one shows any more information than can be
> queried with ethtool, right?
correct, it just displays it in a format that is much more readable
>
> > nic_mac_loopback
> > is to set a port to loopback mode and out of it. It's not really
> > configuration but rather a mode change.
>
> What is this loopback for? Testing?

Correct.

Thanks,
Oded