> -----Original Message-----
> From: Jakub Kicinski <[email protected]>
> Sent: 2021年2月24日 10:35
> To: Joakim Zhang <[email protected]>
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> dl-linux-imx <[email protected]>
> Subject: Re: [PATCH V1 net-next 0/3] net: stmmac: implement clocks
>
> On Wed, 24 Feb 2021 02:13:05 +0000 Joakim Zhang wrote:
> > > > The aim is to enable clocks when it needs, others keep clocks disabled.
> > >
> > > Understood. Please double check ethtool callbacks work fine. People
> > > often forget about those when disabling clocks in .close.
> >
> > Hi Jakub,
> >
> > If NIC is open then clocks are always enabled, so all ethtool
> > callbacks should be okay.
> >
> > Could you point me which ethtool callbacks could be invoked when NIC
> > is closed? I'm not very familiar with ethtool use case. Thanks.
>
> Well, all of them - ethtool does not check if the device is open.
> User can access and configure the device when it's closed.
> Often the callbacks access only driver data, but it's implementation specific
> so
> you'll need to validate the callbacks stmmac implements.
Hi Jakub,
I check the code, ethtool from stmmac driver only can be used when net is
running now, so the clocks are enabled.
net/ethtool/ioctl.c -> dev_ethtool()
[...]
if (dev->ethtool_ops->begin) {
rc = dev->ethtool_ops->begin(dev);
if (rc < 0)
return rc;
}
[...]
Stmmac driver implement begin callback like below:
static int stmmac_check_if_running(struct net_device *dev)
{
if (!netif_running(dev))
return -EBUSY;
return 0;
}
Best Regards,
Joakim Zhang
