netdev - Re: [PATCH] Revert "phy: add support for a reset-gpio specification"

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Message-ID: <b2763da7-575a-4d73-2997-4236173761bf@cogentembedded.com>
Date:	Thu, 19 May 2016 16:11:44 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Fabio Estevam <fabio.estevam@....com>, davem@...emloft.net
Cc:	u.kleine-koenig@...gutronix.de, linux@...ck-us.net,
	f.fainelli@...il.com, netdev@...r.kernel.org
Subject: Re: [PATCH] Revert "phy: add support for a reset-gpio specification"

Hello.

On 5/18/2016 7:05 PM, Fabio Estevam wrote:

> Commit da47b4572056 ("phy: add support for a reset-gpio specification")
> causes the following xtensa qemu crash according to Guenter Roeck:
>
> [    9.366256] libphy: ethoc-mdio: probed
> [    9.367389]  (null): could not attach to PHY
> [    9.368555]  (null): failed to probe MDIO bus
> [    9.371540] Unable to handle kernel paging request at virtual address 0000001c
> [    9.371540]  pc = d0320926, ra = 903209d1
> [    9.375358] Oops: sig: 11 [#1]

    Of course, I'd like this patch to be reverted (as it was applied 
erroneously instead of my patches)... but where's the backtrace? It's not 
immediately clear how this code can cause kernel oops...

> This reverts commit da47b4572056487fd7941c26f73b3e8815ff712a.
>
> Reported-by: Guenter Roeck <linux@...ck-us.net>
> Signed-off-by: Fabio Estevam <fabio.estevam@....com>
[...]
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 307f72a..e977ba9 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
[...]
> @@ -1571,16 +1570,9 @@ static int phy_probe(struct device *dev)
>  	struct device_driver *drv = phydev->mdio.dev.driver;
>  	struct phy_driver *phydrv = to_phy_driver(drv);
>  	int err = 0;
> -	struct gpio_descs *reset_gpios;
>
>  	phydev->drv = phydrv;
>
> -	/* take phy out of reset */
> -	reset_gpios = devm_gpiod_get_array_optional(dev, "reset",
> -						    GPIOD_OUT_LOW);
> -	if (IS_ERR(reset_gpios))
> -		return PTR_ERR(reset_gpios);
> -
>  	/* Disable the interrupt if the PHY doesn't support it
>  	 * but the interrupt is still a valid one
>  	 */

MBR, Sergei