netdev - Re: [PATCH netnext 04/16] net: aquantia: link interrupt handling functions

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Message-ID: <f0f53738-0419-bdee-278e-15ae4eff55c1@gmail.com>
Date:   Sat, 13 Apr 2019 20:26:23 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Igor Russkikh <Igor.Russkikh@...antia.com>,
        Andrew Lunn <andrew@...n.ch>
Cc:     "David S . Miller" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Nikita Danilov <Nikita.Danilov@...antia.com>,
        Dmitry Bogdanov <Dmitry.Bogdanov@...antia.com>
Subject: Re: [PATCH netnext 04/16] net: aquantia: link interrupt handling
 functions

On 13.04.2019 20:22, Igor Russkikh wrote:
> 
> Hi Heiner, Andrew,
> 
> 
>>> If you just schedule a task from the hard irq handler, why not using
>>> a threaded interrupt?
>>
>> Yes, i was just about to say that.
> 
> Thanks, will check that.
> 
>>> And a further question because I worked on the Aquantia PHY driver:
>>> I assume the integrated PHY's are identical or at least very similar
>>> to the external ones like AQR107. Did you ever consider to switch
>>> the PHY handling part of this driver to phylib?  This may help to
>>> reduce complexity and code size of the driver.
>>
>> Hi Heiner
>>
>> I think this was discussed at the time the driver was first
>> submitted. Or it could of been the USB version. The first version did
>> actually allow access to PHY registers, and the MAC driver did poke
>> some of the registers.
>>
>> My guess is, other operating systems don't have a suitable PHY
>> driver. So they pushed it all into firmware. As a result, they now
>> possibly have an inferior experience on Linux than if they used the
>> new PHY driver.
> 
> Not only because of that. Mainly because this product delivers integrated
> mac/phy solution and MAC FW is made to rule all the specific phy configuration
> and subtle work (things like pcie configuration, link interrupts, WOL features,
> etc).
> 
> To use separate phylib driver, FW should be totally disabled, but hardware
> is not designed to run in full featured mode without FW.
> 
> phylib driver could be used, and phy registers access is actually possible
> from host, but using it will definitely cause conflicts with FW.
> 
> Hope that explains the current design. And Andrew is right, very similar
> design is chosen on USB AQC driver we submitted recently.
> 
OK, I see. Thanks for the explanation!

> Regards,
>   Igor
> 
Heiner