netdev - Re: [PATCH net] net: dsa: change PHY error message again

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Message-ID: <08a6381d-ad7d-f1de-6793-be4625014d9b@gmail.com>
Date:   Sun, 23 Aug 2020 20:37:44 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Andrew Lunn <andrew@...n.ch>, Vladimir Oltean <olteanv@...il.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net,
        vivien.didelot@...il.com
Subject: Re: [PATCH net] net: dsa: change PHY error message again



On 8/23/2020 3:26 PM, Andrew Lunn wrote:
> On Mon, Aug 24, 2020 at 12:35:20AM +0300, Vladimir Oltean wrote:
>> slave_dev->name is only populated at this stage if it was specified
>> through a label in the device tree. However that is not mandatory.
> 
> Hi Vladimir
> 
> It is not mandatory, but it is normal.
> 
>> When it isn't, the error message looks like this:
>>
>> [    5.037057] fsl_enetc 0000:00:00.2 eth2: error -19 setting up slave PHY for eth%d
>> [    5.044672] fsl_enetc 0000:00:00.2 eth2: error -19 setting up slave PHY for eth%d
>> [    5.052275] fsl_enetc 0000:00:00.2 eth2: error -19 setting up slave PHY for eth%d
>> [    5.059877] fsl_enetc 0000:00:00.2 eth2: error -19 setting up slave PHY for eth%d
>>
>> which is especially confusing since the error gets printed on behalf of
>> the DSA master (fsl_enetc in this case).
>>
>> Printing an error message that contains a valid reference to the DSA
>> port's name is difficult at this point in the initialization stage, so
>> at least we should print some info that is more reliable, even if less
>> user-friendly. That may be the driver name and the hardware port index.
>>
>> After this change, the error is printed as:
>>
>> [    4.957403] mscc_felix 0000:00:00.5: error -19 setting up PHY for port 0
>> [    4.964231] mscc_felix 0000:00:00.5: error -19 setting up PHY for port 1
>> [    4.971055] mscc_felix 0000:00:00.5: error -19 setting up PHY for port 2
>> [    4.977871] mscc_felix 0000:00:00.5: error -19 setting up PHY for port 3
> 
> I would prefer both the port number and the interface name. With
> setups using D in DSA, there are examples where port 1 on the first
> switch is lan1, and port 1 of the second switch is lan5. Having both
> avoids some confusion.

How about printing the tree, switch id and port number that way we have 
all the uniquely identifying information at hand?

> 
> Another option would be to call dev_alloc_name() after
> alloc_netdev_mqs() if there is no label. The eth%d will then get
> replaced with a unique name.

That would work, too.

> 
>> Fixes: 65951a9eb65e ("net: dsa: Improve subordinate PHY error message")
> 
> I'm not sure this actually meets the stable criteria.

Agreed this might be a little bit too much.
-- 
Florian