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From:   Min Li <min.li.xe@renesas.com>
To:     Richard Cochran <richardcochran@gmail.com>
CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net 2/2] ptp: idt82p33: implement double dco time
 correction
Thread-Topic: [PATCH net 2/2] ptp: idt82p33: implement double dco time
 correction
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Date:   Thu, 24 Jun 2021 14:40:52 +0000
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> -----Original Message-----
> From: Richard Cochran <richardcochran@gmail.com>
> Sent: June 23, 2021 11:44 PM
> To: Min Li <min.li.xe@renesas.com>
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH net 2/2] ptp: idt82p33: implement double dco time
> correction
>=20
> On Wed, Jun 23, 2021 at 10:46:25AM -0400, min.li.xe@renesas.com wrote:
> > +static int idt82p33_start_ddco(struct idt82p33_channel *channel, s32
> > +delta_ns) {
> > +	s32 current_ppm =3D channel->current_freq;
> > +	u32 duration_ms =3D MSEC_PER_SEC;
>=20
> What happens if user space makes a new adjustment before this completes?
>=20
> After all, some PTP profiles update the clock several times per second.
>=20
> Thanks,
> Richard

Hi Richard

In that case, adjtime would simply return without doing anything as in

@@ -848,11 +914,15 @@ static int idt82p33_adjtime(struct ptp_clock_info *pt=
p, s64 delta_ns)
 	struct idt82p33 *idt82p33 =3D channel->idt82p33;
 	int err;
=20
+	if (channel->ddco =3D=3D true)
+		return 0;
+