Re: [PATCH] smsc911x: power-up phydev before doing a software reset.

[David Miller <davem@davemloft.net>]

From: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Date: Mon, 10 Nov 2014 19:23:09 +0100

> With commit be9dad1f9f26604fb ("net: phy: suspend phydev when going
> to HALTED"), the PHY device will be put in a low-power mode using
> BMCR_PDOWN if the the interface is set down. The smsc911x driver does
> a software_reset opening the device driver (ndo_open). In such case,
> the PHY must be powered-up before access to any register and before
> calling the software_reset function. Otherwise, as the PHY is powered
> down the software reset fails and the interface can not be enabled
> again.
> 
> This patch fixes this scenario that is easy to reproduce setting down
> the network interface and setting up again.
> 
>     $ ifconfig eth0 down
>     $ ifconfig eth0 up
>     ifconfig: SIOCSIFFLAGS: Input/output error
> 
> Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
 ...
> +		mdelay(1);

As per Javier's feedback, please convert this to usleep_range()
if you agree that this can only be invoked from process context.

Thanks.