Messages in this thread | | | Date | Fri, 6 Jan 2023 18:21:26 -0500 | Subject | Re: [PATCH net-next v5 4/4] phy: aquantia: Determine rate adaptation support from registers | From | Sean Anderson <> |
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On 1/6/23 18:03, Vladimir Oltean wrote: > On Thu, Jan 05, 2023 at 05:46:48PM +0000, Russell King (Oracle) wrote: >> On Thu, Jan 05, 2023 at 07:34:45PM +0200, Vladimir Oltean wrote: >> > So we lose the advertisement of 5G and 2.5G, even if the firmware is >> > provisioned for them via 10GBASE-R rate adaptation, right? Because when >> > asked "What kind of rate matching is supported for 10GBASE-R?", the >> > Aquantia driver will respond "None". >> >> The code doesn't have the ability to do any better right now - since >> we don't know what sets of interface modes _could_ be used by the PHY >> and whether each interface mode may result in rate adaption. >> >> To achieve that would mean reworking yet again all the phylink >> validation from scratch, and probably reworking phylib and most of >> the PHY drivers too so that they provide a lot more information >> about their host interface behaviour. >> >> I don't think there is an easy way to have a "perfect" solution >> immediately - it's going to take a while to evolve - and probably >> painfully evolve due to the slowness involved in updating all the >> drivers that make use of phylink in some way. > > Serious question. What do we gain in practical terms with this patch set > applied? With certain firmware provisioning, some unsupported link modes > won't be advertised anymore. But also, with other firmware, some supported > link modes won't be advertised anymore.
Well, before the rate adaptation series, none of this would be advertised. I would rather add advertisement only for what we can actually support. We can always come back later and add additional support.
> IIUC, Tim Harvey's firmware ultimately had incorrect provisioning, it's > not like the existing code prevents his use case from working.
The existing code isn't great as-is, since all the user sees is that we e.g. negotiated for 1G, but the link never came up.
--Sean
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