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From: Steve Bennett <>
To: Ben Hutchings <>
Cc: Jakub Kicinski <>,,
Subject: Re: [PATCH] net: phy: micrel: Fix detection of ksz87xx switch
Date: Mon, 9 Aug 2021 08:18:28 +1000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20210807000123.GA4898@cephalopod>

> On 7 Aug 2021, at 10:01 am, Ben Hutchings <> wrote:
> On Sat, Jul 31, 2021 at 08:19:17AM +1000, Steve Bennett wrote:
>>> On 31 Jul 2021, at 2:59 am, Jakub Kicinski <> wrote:
>>> Please extend the CC list to the maintainers, and people who
>>> worked on this driver in the past, especially Marek.
>> Sure, I can do that in a v2 of the patch along with the more detailed
>> explanation below.
>>> On Fri, 30 Jul 2021 20:51:20 +1000 Steve Bennett wrote:
>>>> The previous logic was wrong such that the ksz87xx
>>>> switch was not identified correctly.
>>> Any more details of what is happening? Which extact device do you see
>>> this problem on?
>> I have a ksz8795 switch.
>> Without the patch:
>> ksz8795-switch spi3.1 ade1 (uninitialized): PHY [dsa-0.1:03] driver [Generic PHY]
>> ksz8795-switch spi3.1 ade2 (uninitialized): PHY [dsa-0.1:04] driver [Generic PHY]
>> With the patch:
>> ksz8795-switch spi3.1 ade1 (uninitialized): PHY [dsa-0.1:03] driver [Micrel KSZ87XX Switch]
>> ksz8795-switch spi3.1 ade2 (uninitialized): PHY [dsa-0.1:04] driver [Micrel KSZ87XX Switch]
> [...]
> And do the external ports work for you after this?
> I have a development board with a KSZ8795.  All ports worked before
> this patch.  After this patch, when I bring up the external ports they
> are reported as having link up at 10M half duplex, when the link is
> actually down.
> The ksz8873mll_read_status() function is trying to read a non-standard
> MDIO register that is not handled by the ksz8795 driver's MDIO
> emulation (and is not documented as existing on the KSZ8873MLL,
> either!).  It also also reports link up, which is obviously not
> correct for an external port.
> I'll post a patch as a reply to this.
> Ben.

Thanks Ben,

That looks reasonable to me. My board is running the external ports at 10HD so
I didn't pick this up, but your patch looks correct.


  parent reply	other threads:[~2021-08-08 22:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 10:51 Steve Bennett
2021-07-30 16:59 ` Jakub Kicinski
2021-07-30 22:19   ` Steve Bennett
2021-08-07  0:01     ` Ben Hutchings
2021-08-07  0:06       ` [PATCH net] net: phy: micrel: Fix link detection on ksz87xx switch" Ben Hutchings
2021-08-08 11:10         ` patchwork-bot+netdevbpf
2021-08-08 22:18       ` Steve Bennett [this message]
2021-07-30 22:57 ` [PATCH v2] net: phy: micrel: Fix detection of ksz87xx switch Steve Bennett
2021-07-30 23:08   ` Marek Vasut
2021-08-02 14:10   ` patchwork-bot+netdevbpf

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