From: Michael Walle <michael@walle.cc>
To: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
Florian Fainelli <f.fainelli@gmail.com>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
David Miller <davem@davemloft.net>,
netdev@vger.kernel.org
Subject: Re: [PATCH net] net: phy: avoid clearing PHY interrupts twice in irq handler
Date: Sun, 01 Mar 2020 23:52:16 +0100 [thread overview]
Message-ID: <a0b161ebd332c9ea26bb62ccf73d1862@walle.cc> (raw)
In-Reply-To: <2f468a46-e966-761c-8466-51601d8f11a3@gmail.com>
Am 2020-03-01 21:36, schrieb Heiner Kallweit:
> On all PHY drivers that implement did_interrupt() reading the interrupt
> status bits clears them. This means we may loose an interrupt that
> is triggered between calling did_interrupt() and phy_clear_interrupt().
> As part of the fix make it a requirement that did_interrupt() clears
> the interrupt.
Looks good. But how would you use did_interrupt() and handle_interrupt()
together? I guess you can't. At least not if handle_interrupt() has
to read the pending bits again. So you'd have to handle custom
interrupts in did_interrupt(). Any idea how to solve that?
[I know, this is only about fixing the lost interrupts.]
-michael
>
> The Fixes tag refers to the first commit where the patch applies
> cleanly.
>
> Fixes: 49644e68f472 ("net: phy: add callback for custom interrupt
> handler to struct phy_driver")
> Reported-by: Michael Walle <michael@walle.cc>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> drivers/net/phy/phy.c | 3 ++-
> include/linux/phy.h | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index d76e038cf..16e3fb79e 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -727,7 +727,8 @@ static irqreturn_t phy_interrupt(int irq, void
> *phy_dat)
> phy_trigger_machine(phydev);
> }
>
> - if (phy_clear_interrupt(phydev))
> + /* did_interrupt() may have cleared the interrupt already */
> + if (!phydev->drv->did_interrupt && phy_clear_interrupt(phydev))
> goto phy_err;
> return IRQ_HANDLED;
>
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 80f8b2158..8b299476b 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -557,6 +557,7 @@ struct phy_driver {
> /*
> * Checks if the PHY generated an interrupt.
> * For multi-PHY devices with shared PHY interrupt pin
> + * Set interrupt bits have to be cleared.
> */
> int (*did_interrupt)(struct phy_device *phydev);
next prev parent reply other threads:[~2020-03-01 22:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-01 20:36 [PATCH net] net: phy: avoid clearing PHY interrupts twice in irq handler Heiner Kallweit
2020-03-01 22:52 ` Michael Walle [this message]
2020-03-01 23:20 ` Heiner Kallweit
2020-03-04 12:13 ` Heiner Kallweit
2020-03-04 13:02 ` Michael Walle
2020-03-02 3:05 ` David Miller
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