netdev - Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on GPY215 by default

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Message-ID: <69e0468cf192455fd2dc7fc93194a8ff@walle.cc>
Date:   Sat, 03 Dec 2022 00:09:07 +0100
From:   Michael Walle <michael@...le.cc>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Xu Liang <lxu@...linear.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on
 GPY215 by default

Am 2022-12-02 19:42, schrieb Andrew Lunn:
> On Fri, Dec 02, 2022 at 04:12:04PM +0100, Michael Walle wrote:
>> The interrupts on the GPY215B and GPY215C are broken and the only 
>> viable
>> fix is to disable them altogether. There is still the possibilty to
>> opt-in via the device tree.
>> 
>> Signed-off-by: Michael Walle <michael@...le.cc>
>> ---
>>  drivers/net/phy/mxl-gpy.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>> 
>> diff --git a/drivers/net/phy/mxl-gpy.c b/drivers/net/phy/mxl-gpy.c
>> index 20e610dda891..edb8cd8313b0 100644
>> --- a/drivers/net/phy/mxl-gpy.c
>> +++ b/drivers/net/phy/mxl-gpy.c
>> @@ -12,6 +12,7 @@
>>  #include <linux/mutex.h>
>>  #include <linux/phy.h>
>>  #include <linux/polynomial.h>
>> +#include <linux/property.h>
>>  #include <linux/netdevice.h>
>> 
>>  /* PHY ID */
>> @@ -290,6 +291,10 @@ static int gpy_probe(struct phy_device *phydev)
>>  	phydev->priv = priv;
>>  	mutex_init(&priv->mbox_lock);
>> 
>> +	if (gpy_has_broken_mdint(phydev) &&
>> +	    !device_property_present(dev, 
>> "maxlinear,use-broken-interrupts"))
>> +		phydev->irq = PHY_POLL;
>> +
> 
> I'm not sure of ordering here. It could be phydev->irq is set after
> probe. The IRQ is requested as part of phy_connect_direct(), which is
> much later.

I've did it that way, because phy_probe() also sets phydev->irq = 
PHY_POLL
in some cases and the phy driver .probe() is called right after it.

> I think a better place for this test is in gpy_config_intr(), return
> -EOPNOTSUPP. phy_enable_interrupts() failing should then cause
> phy_request_interrupt() to use polling.

Which will then print a warning, which might be misleading.
Or we disable the warning if -EOPNOTSUPP is returned?

-michael