Re: [PATCH net 2/3] net: phy: micrel: Remove latency from driver

[Allan W. Nielsen]

On 01.04.2022 15:34, Horatiu Vultur wrote:
> The 04/01/2022 14:47, Andrew Lunn wrote:
> > On Fri, Apr 01, 2022 at 11:48:04AM +0200, Horatiu Vultur wrote:
> > > Based on the discussions here[1], the PHY driver is the wrong place
> > > to set the latencies, therefore remove them.
> > >
> > > [1] https://lkml.org/lkml/2022/3/4/325
> > >
> > > Fixes: ece19502834d84 ("net: phy: micrel: 1588 support for LAN8814 phy")
> > > Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> >
> > Thanks for the revert.
> >
> > Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
> >
> > > -static struct kszphy_latencies lan8814_latencies = {
> > > -     .rx_10          = 0x22AA,
> > > -     .tx_10          = 0x2E4A,
> > > -     .rx_100         = 0x092A,
> > > -     .tx_100         = 0x02C1,
> > > -     .rx_1000        = 0x01AD,
> > > -     .tx_1000        = 0x00C9,
> > > -};
> >
> > What are the reset defaults of these?
>
> Those are actually the reset values.
>
> > I'm just wondering if we should
> > explicitly set them to 0, so we don't get into a mess where some
> > vendor bootloader sets values but mainline bootloader does not,
> > breaking a configuration where the userspace daemon does the correct?
>
> It would be fine for me to set them to 0. But then definitely we need a
> way to set these latencies from userspace.
I would like to keep the default values. With default values, you can
get PTP working (accuracy is not great - but it is much better than
if set to zero).

There is no risk of bootloaders to pre-load other values, as the kernel
will reset the PHY, and after reset we will be back to these numbers.

/Allan