Messages in this thread | | | Date | Thu, 3 Oct 2019 22:10:34 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH 0/2] net: phy: broadcom: RGMII delays fixes |
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On Thu, Oct 03, 2019 at 10:54:26PM +0300, Vladimir Oltean wrote: > Hi Andrew, > > On Thu, 3 Oct 2019 at 22:06, Andrew Lunn <andrew@lunn.ch> wrote: > > > > On Thu, Oct 03, 2019 at 11:55:40AM -0700, Florian Fainelli wrote: > > > Hi Andrew, > > > > > > On 10/3/19 11:51 AM, Andrew Lunn wrote: > > > > On Thu, Oct 03, 2019 at 11:43:50AM -0700, Florian Fainelli wrote: > > > >> Hi all, > > > >> > > > >> This patch series fixes the BCM54210E RGMII delay configuration which > > > >> could only have worked in a PHY_INTERFACE_MODE_RGMII configuration. > > > > > > > > Hi Florian > > > > > > > > So any DT blob which incorrectly uses one of the other RGMII modes is > > > > now going to break, where as before it was ignored. > > > > > > Potentially yes. There is a precedent with the at803x PHY driver > > > > Hi Florian > > > > Yes that was an interesting learning experience. I'm not sure we want > > to do that again. A lot of devices broken, and a lot of people were > > unhappy. > > > > If we are looking at a similar scale of breakage, i think i would > > prefer to add a broadcom,bcm54210e-phy-mode property in the DT which > > if present would override the phy_interface_t passed to the driver. > > > > Andrew > > What is the breakage concern here?
With the at803x, we had a lot of devices which said rgmii in there DT, but actually needed rgmii-id. The driver however did not do anything, and the silicon defaulted to rgmii-id, so things just worked, the two bugs cancelling each other out.
Then a board come along which really did need rgmii. Adding support to actually correctly configure the RGMII delays then broke all the boards with the wrong value in DT.
> But in this case, the only breakage would be "hmmm, let's just enable > RGMII delays everywhere. So it works with rgmii-id on both the PHY and > the MAC side of things? Great, time for lunch!". I just hope that did > not happen.
That is my hope as well. But letting it sit in net-next for a while might help confirm that hope. As i said, at803x was painful, and i would like to avoid that again. So i'm being more cautious.
Andrew
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