Hi Saravana, On 14.09.2021 06:44, Saravana Kannan wrote: > On Mon, Sep 13, 2021 at 5:54 PM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: >> On Thu, Sep 9, 2021 at 1:03 AM Marek Szyprowski >> <m.szyprowski@xxxxxxxxxxx> wrote: >>> On 08.09.2021 23:58, Saravana Kannan wrote: >>>> This is a test patch. I'll split it up into multiple commits and clean >>>> it up once it's shown to help. >>>> >>>> Marek, can you please test this and let me know if it helps? >>> I've just checked and nope, it doesn't help for my case. Ethernet is >>> still not probed on Amlogic G12A/B SoC based boards. :( >> Hi Marek, >> >> Thanks for testing out the patch. Turns out the issue was a lot more >> complicated than I thought. Thanks to a bunch of debug logs that Rob >> provided off-list, I was able to root cause the actual issue. >> >> Looks like the problem is cyclic dependency between the mdio-multiplexer and the >> ethernet: >> ethmac -(phy-handle)-> external_phy -(parent) -> >> mdio-multiplexer -(mdio-bus-parent)-> mdio0 -(parent)-> ethmac >> >> Relevant parts of the DT combined from multiple files and trimmed and >> pasted below. >> >> If fw_devlink sees a cycle, it'll stop enforcing ordering between all >> the devices in the cycle since it can't figure out which one of the >> dependencies isn't real. So, the confusing part was that, when Andrew >> Lunn gave the patch for adding support for "mdio-bus-parent", that >> should have allowed fw_devlink to see the cycle and stop enforcing the >> dependencies. But that didn't happen because of a bug in fw_devlink >> cycle handling (it worked for most cases, but not for this specific >> ordering in DT). I'll send out a fix for that soon. > Here's the fix I promised: > https://lore.kernel.org/lkml/20210914043928.4066136-2-saravanak@xxxxxxxxxx/ > >> That combined with >> Andrew's "mdio-bus-parent" patch should fix things for you. > Fairly certain the fix above and Andrew's patch should fix it for you > if you want to test it. Rob already verified a very similar patch for me. Right. Those both patches finally fixed the ethernet issue. Feel free to add: Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
