linux-kernel - Re: [PATCH net-next 1/2] net: phy: broadcom: set features explicitly for BCM54616S

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Message-ID: <85331173-da14-5fcd-8c80-5bd2883061ec@fb.com>
Date:   Fri, 2 Aug 2019 01:29:36 +0000
From:   Tao Ren <taoren@...com>
To:     Heiner Kallweit <hkallweit1@...il.com>,
        Andrew Lunn <andrew@...n.ch>
CC:     Florian Fainelli <f.fainelli@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Arun Parameswaran <arun.parameswaran@...adcom.com>,
        Justin Chen <justinpopo6@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Jeffery <andrew@...id.au>,
        "openbmc@...ts.ozlabs.org" <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH net-next 1/2] net: phy: broadcom: set features explicitly
 for BCM54616S

On 7/31/19 10:20 PM, Tao Ren wrote:
> On 7/30/19 11:00 PM, Tao Ren wrote:
>> On 7/30/19 10:53 PM, Heiner Kallweit wrote:
>>> On 31.07.2019 02:12, Tao Ren wrote:
>>>> On 7/29/19 11:00 PM, Heiner Kallweit wrote:
>>>>> On 30.07.2019 07:05, Tao Ren wrote:
>>>>>> On 7/29/19 8:35 PM, Andrew Lunn wrote:
>>>>>>> On Mon, Jul 29, 2019 at 05:25:32PM -0700, Tao Ren wrote:
>>>>>>>> BCM54616S feature "PHY_GBIT_FEATURES" was removed by commit dcdecdcfe1fc
>>>>>>>> ("net: phy: switch drivers to use dynamic feature detection"). As dynamic
>>>>>>>> feature detection doesn't work when BCM54616S is working in RGMII-Fiber
>>>>>>>> mode (different sets of MII Control/Status registers being used), let's
>>>>>>>> set "PHY_GBIT_FEATURES" for BCM54616S explicitly.
>>>>>>>
>>>>>>> Hi Tao
>>>>>>>
>>>>>>> What exactly does it get wrong?
>>>>>>>
>>>>>>>      Thanks
>>>>>>> 	Andrew
>>>>>>
>>>>>> Hi Andrew,
>>>>>>
>>>>>> BCM54616S is set to RGMII-Fiber (1000Base-X) mode on my platform, and none of the features (1000BaseT/100BaseT/10BaseT) can be detected by genphy_read_abilities(), because the PHY only reports 1000BaseX_Full|Half ability in this mode.
>>>>>>
>>>>> Are you going to use the PHY in copper or fibre mode?
>>>>> In case you use fibre mode, why do you need the copper modes set as supported?
>>>>> Or does the PHY just start in fibre mode and you want to switch it to copper mode?
>>>>
>>>> Hi Heiner,
>>>>
>>>> The phy starts in fiber mode and that's the mode I want.
>>>> My observation is: phydev->link is always 0 (Link status bit is never set in MII_BMSR) by using dynamic ability detection on my machine. I checked phydev->supported and it's set to "AutoNeg | TP | MII | Pause | Asym_Pause" by dynamic ability detection. Is it normal/expected? Or maybe the fix should go to different places? Thank you for your help.
>>>>
>>>
>>> Not sure whether you stated already which kernel version you're using.
>>> There's a brand-new extension to auto-detect 1000BaseX:
>>> f30e33bcdab9 ("net: phy: Add more 1000BaseX support detection")
>>> It's included in the 5.3-rc series.
>>
>> I'm running kernel 5.2.0. Thank you for the sharing and I didn't know the patch. Let me check it out.
> 
> I applied above patch and ca72efb6bdc7 ("net: phy: Add detection of 1000BaseX link mode support") to my 5.2.0 tree but got following warning when booting up my machine:
> 
> "PHY advertising (0,00000200,000062c0) more modes than genphy supports, some modes not advertised".
> 
> The BCM54616S PHY on my machine only reports 1000-X features in RGMII->1000Base-KX mode. Is it a known problem?
> 
> Anyways let me see if I missed some dependency/follow-up patches..

Let's ignore the patch ("net: phy: broadcom: set features explicitly for BCM54616S"): as Heiner pointed out, it doesn't make sense to turn on copper features for fiber mode (even though it "works" in my environment). I will work out new patch if 1000bx-auto-detection patches cannot solve my problem.

Thank you all for spending time on this.


Cheers,

Tao