netdev - Re: [PATCH V2] net: phy: tja11xx: Add IRQ support to the driver

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Message-ID: <20190617171613.GJ17551@lunn.ch>
Date:   Mon, 17 Jun 2019 19:16:13 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Marek Vasut <marex@...x.de>
Cc:     Heiner Kallweit <hkallweit1@...il.com>, netdev@...r.kernel.org,
        Florian Fainelli <f.fainelli@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH V2] net: phy: tja11xx: Add IRQ support to the driver

On Thu, Jun 13, 2019 at 05:42:53PM +0200, Marek Vasut wrote:
> On 5/30/19 1:46 AM, Marek Vasut wrote:
> > On 5/30/19 1:29 AM, Andrew Lunn wrote:
> >> On Tue, May 28, 2019 at 11:33:33PM +0200, Marek Vasut wrote:
> >>> On 5/28/19 11:22 PM, Andrew Lunn wrote:
> >>>>> The link detection on the TJA1100 (not TJA1101) seems unstable at best,
> >>>>> so I better use all the interrupt sources to nudge the PHY subsystem and
> >>>>> have it check the link change.
> >>>>
> >>>> Then it sounds like you should just ignore interrupts and stay will
> >>>> polling for the TJA1100.
> >>>
> >>> Polling for the link status change is slow(er) than the IRQ driven
> >>> operation, so I would much rather use the interrupts.
> >>
> >> I agree about the speed, but it seems like interrupts on this PHY are
> >> not so reliable. Polling always works. But unfortunately, you cannot
> >> have both interrupts and polling to fix up problems when interrupts
> >> fail. Your call, do you think interrupts really do work?
> > 
> > It works fine for me this way. And mind you, it's only the TJA1100
> > that's flaky, the TJA1101 is better.
> > 
> >> If you say that tja1101 works as expected, then please just use the
> >> link up/down bits for it.
> > 
> > I still don't know which bits really trigger link status changes, so I'd
> > like to play it safe and just trigger on all of them.
> 
> So what do we do here ?

Hi Marek

My personal preference would be to just enable what is needed. But
I won't block a patch which enables everything.

  Andrew