linux-kernel - Re: [PATCH] net: phy: Ensure the state machine is called when phy is UP

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Message-ID: <19a526d3-f798-bbb8-328d-9eff18d17eb0@atmel.com>
Date:   Mon, 19 Sep 2016 15:15:38 +0200
From:   Nicolas Ferre <nicolas.ferre@...el.com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        <netdev@...r.kernel.org>
CC:     "David S . Miller" <davem@...emloft.net>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] net: phy: Ensure the state machine is called when phy is
 UP

Hi all,

I come back to this thread to re-start the conversation as I still have
the issue...


Le 16/04/2016 à 00:45, Alexandre Belloni a écrit :
> On 16/04/2016 at 00:30:26 +0200, Andrew Lunn wrote :
>> On Sat, Apr 16, 2016 at 12:17:11AM +0200, Alexandre Belloni wrote:
>>> On 16/04/2016 at 00:05:08 +0200, Andrew Lunn wrote :
>>>>> Trace without my patch:
>>>>> libphy: MACB_mii_bus: probed
>>>>> macb f8020000.ethernet eth0: Cadence GEM rev 0x00020120 at 0xf8020000 irq 27 (fc:c2:3d:0c:6e:05)
>>>>> Micrel KSZ8081 or KSZ8091 f8020000.etherne:01: attached PHY driver [Micrel KSZ8081 or KSZ8091] (mii_bus:phy_addr=f8020000.etherne:01, irq=171)
>>>>> Micrel KSZ8081 or KSZ8091 f8020000.etherne:01: PHY state change READY -> READY
>>>>> [...]
>>>>> Micrel KSZ8081 or KSZ8091 f8020000.etherne:01: PHY state change READY -> READY
>>>>
>>>> Are there some state changes before this? How is it getting to state
>>>> READY? It would expect it to start in DOWN, from when the phy device
>>>> was created in phy_device_create().
>>>>
>>>
>>> No other changes. I forgot to mention that this is when booting with a
>>> cable plugged in. Unplugging and replugging the cable makes the link
>>> detection work fine even without the patch.
>>
>> Are you tftpbooting? I.e. has the boot loader already done an auto
>> negotiation?
>>
> 
> Yes.

Yes indeed: this is my use-case: load the kernel from U-Boot using tftp
and having the rootfs in NAND flash so, no NFS rootfs for me.

>> I've looked at the code and i still don't see how it gets to READY.
>> What i do see is that when you connect the phy to the MAC, the
>> interrupt handler is installed. So maybe there are some PHY interrupts
>> before the interface is opened? Could you put a print in
>> phy_interrupt().
>>
> 
> That is indeed the case, and I'm not sure why because
> 99f81afc139c6edd14d77a91ee91685a414a1c66 is trying to disable AN at
> boot.

I don't know what happens to the phy, but this patch does fix the issue
for me:
Tested-by: Nicolas Ferre <nicolas.ferre@...el.com>

The other alternative that I'm considering seriously as I'm still
struggled with this is to simply remove the phy IRQ from my board DT.

Best regards,
-- 
Nicolas Ferre