Messages in this thread | | | Date | Thu, 5 Jan 2023 14:00:23 -0500 | Subject | Re: [PATCH net-next v5 4/4] phy: aquantia: Determine rate adaptation support from registers | From | Sean Anderson <> |
| |
On 1/5/23 13:58, Russell King (Oracle) wrote: > On Thu, Jan 05, 2023 at 01:03:49PM -0500, Sean Anderson wrote: >> On 1/5/23 12:55, Vladimir Oltean 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. >> >> As for Layerscape boards, SERDES protocol switching is a very new concept there, >> >> so they're all going to be provisioned for PAUSE all the way down >> >> (or USXGMII, where that is available). >> >> >> >> I just pointed this out because it jumped out to me. I don't have >> >> something against this patch getting accepted as it is. >> > >> > A real-life (albeit niche) scenario where someone might have an Aquantia >> > firmware provisioned like this would be a 10G capable port that also >> > wants to support half duplex at 10/100 speeds. Although I'm not quite >> > sure who cares about half duplex all that much these days. >> >> IMO if we really want to support this, the easier way would be to teach >> the phy driver how to change the rate adaptation mode. That way we could >> always advertise rate adaptation, but if someone came along and >> requested 10HD we could reconfigure the phy to support it. However, this >> was deemed too risky in the discussion for v1, since we don't really >> know how the firmware interacts with the registers. > > I'm not sure about "someone came along and requested 10HD". Don't you > mean "if someone plugged the RJ45 into a 10bT hub which only supports > 10HD" ? Or are you suggesting that we shouldn't advertise 10HD and > 100HD along with everything else, and then switch into this special > mode if someone wants to advertise these and disable all other link > modes? >
The former. "someone" being userspace or the remote end.
--Sean
| |