Subject: Re: [PATCH iwl-next v3 3/3] ice: Implement driver functionality to dump serdes equalizer values

From: Simon Horman <[email-masked]>
Date: Mon, 17 Jun 2024 15:52:42 +0100

On Fri, Jun 14, 2024 at 05:55:59PM -0700, Jakub Kicinski wrote:
> On Fri, 14 Jun 2024 05:58:17 -0700 Anil Samal wrote:
> > To debug link issues in the field, serdes Tx/Rx equalizer values
> > help to determine the health of serdes lane.
> > 
> > Extend 'ethtool -d' option to dump serdes Tx/Rx equalizer.
> > The following list of equalizer param is supported
> >     a. rx_equalization_pre2
> >     b. rx_equalization_pre1
> >     c. rx_equalization_post1
> >     d. rx_equalization_bflf
> >     e. rx_equalization_bfhf
> >     f. rx_equalization_drate
> >     g. tx_equalization_pre1
> >     h. tx_equalization_pre3
> >     i. tx_equalization_atten
> >     j. tx_equalization_post1
> >     k. tx_equalization_pre2
> 
> I'd be tempted to create a dedicated way to dump vendor specific signal
> quality indicators (both for Ethernet and PCIe). Feels little cleaner
> than appending to a flat mixed-purpose dump. But either way is fine by
> me, TBH. Much better than vendor tools poking into the BAR...

+1

In particular, I agree that either way ethtool -d is
better than than vendor tools poking into the BAR.
Because the Kernel can mediate access to the hardware
and see the data.