netdev - Re: [PATCH] net: phy: realtek: clear interrupt during init for rtl8211f

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Date:   Thu, 14 May 2020 14:25:37 +0800
From:   Jisheng Zhang <Jisheng.Zhang@...aptics.com>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: phy: realtek: clear interrupt during init for
 rtl8211f

On Wed, 13 May 2020 20:45:13 +0200 Heiner Kallweit wrote:

> 
> On 13.05.2020 08:51, Jisheng Zhang wrote:
> > Hi,
> >
> > On Tue, 12 May 2020 20:43:40 +0200 Heiner Kallweit wrote:
> >  
> >>
> >>
> >> On 12.05.2020 12:46, Jisheng Zhang wrote:  
> >>> The PHY Register Accessible Interrupt is enabled by default, so
> >>> there's such an interrupt during init. In PHY POLL mode case, the
> >>> INTB/PMEB pin is alway active, it is not good. Clear the interrupt by
> >>> calling rtl8211f_ack_interrupt().  
> >>
> >> As you say "it's not good" w/o elaborating a little bit more on it:
> >> Do you face any actual issue? Or do you just think that it's not nice?  
> >
> >
> > The INTB/PMEB pin can be used in two different modes:
> > INTB: used for interrupt
> > PMEB: special mode for Wake-on-LAN
> >
> > The PHY Register Accessible Interrupt is enabled by
> > default, there's always such an interrupt during the init. In PHY POLL mode
> > case, the pin is always active. If platforms plans to use the INTB/PMEB pin
> > as WOL, then the platform will see WOL active. It's not good.
> >  
> The platform should listen to this pin only once WOL has been configured and
> the pin has been switched to PMEB function. For the latter you first would
> have to implement the set_wol callback in the PHY driver.
> Or where in which code do you plan to switch the pin function to PMEB?

I think it's better to switch the pin function in set_wol callback. But this
is another story. No matter WOL has been configured or not, keeping the
INTB/PMEB pin active is not good. what do you think?

> One more thing to consider when implementing set_wol would be that the PHY
> supports two WOL options:
> 1. INT/PMEB configured as PMEB
> 2. INT/PMEB configured as INT and WOL interrupt source active
> 
> >  
> >> I'm asking because you don't provide a Fixes tag and you don't
> >> annotate your patch as net or net-next.  
> >
> > should be Fixes: 3447cf2e9a11 ("net/phy: Add support for Realtek RTL8211F")
> >  
> >> Once you provide more details we would also get an idea whether a
> >> change would have to be made to phylib, because what you describe
> >> doesn't seem to be specific to this one PHY model.  
> >
> > Nope, we don't need this change in phylib, this is specific to rtl8211f
> >
> > Thanks,
> > Jisheng
> >  
> Heiner