Re: [PATCH net-next v5 4/4] phy: aquantia: Determine rate adaptation support from registers

[Sean Anderson]

On 1/5/23 13:55, Russell King (Oracle) wrote:
> On Thu, Jan 05, 2023 at 07:52:06PM +0200, Vladimir Oltean wrote:
>> On Thu, Jan 05, 2023 at 12:43:47PM -0500, Sean Anderson wrote:
>> > Again, this is to comply with the existing API assumptions. The current
>> > code is buggy. Of course, another way around this is to modify the API.
>> > I have chosen this route because I don't have a situation like you
>> > described. But if support for that is important to you, I encourage you
>> > to refactor things.
>> 
>> I don't think I'm aware of a practical situation like that either.
>> I remember seeing some S32G boards with Aquantia PHYs which use 2500BASE-X
>> for 2.5G and SGMII for <=1G, but that's about it in terms of protocol switching.
> 
> 88x3310 can dynamically switch between 10GBASE-R, 5GBASE-R, 2500BASE-X
> and SGMII if rate adaption is not being used (and the rate adaption
> method it supports in non-MACSEC PHYs is only via increasing the IPG on
> the MAC... which currently no MAC driver supports.)
> 

As an aside, do you know of any MACs which support open-loop rate
matching to below ~95% of the line rate (the amount necessary for
10GBASE-W)?

--Sean