netdev - Re: [PATCH] [RFC] net: phy: phy drivers should not set SUPPORTED_Pause or SUPPORTED_Asym

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Date:   Tue, 1 Nov 2016 11:35:43 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Timur Tabi <timur@...eaurora.org>,
        David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] [RFC] net: phy: phy drivers should not set
 SUPPORTED_Pause or SUPPORTED_Asym_Pause

On 11/01/2016 10:18 AM, Timur Tabi wrote:
> Pause frames are a feature that is supported by the MAC.  It is the MAC
> that generates the frames and that processes them.  Thy PHY can only be
> configured to allow them to pass.  Therefore, pause frame support in the
> PHY should only be enabled if the MAC wants it enabled.  It should not be
> forced on all the time.
> 
> Signed-off-by: Timur Tabi <timur@...eaurora.org>

So in premise, this is good, and is exactly what I have in mind for the
series that I am cooking, but if we apply this alone, without a change
in drivers/net/phy/phy.c which adds SUPPORTED_Pause |
SUPPORTED_AsymPause to phydev->features, we are basically breaking the
Ethernet MAC drivers that don't explicitly override phydev->features and
yet rely on that to get flow control to work.
-- 
Florian