RE: [PATCH net 2/2] ptp: idt82p33: implement double dco time correction

-----Original Message-----
From: Richard Cochran <richardcochran@gmail.com>
Sent: June 23, 2021 11:44 PM
To: Min Li <redacted>
Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 2/2] ptp: idt82p33: implement double dco time
correction

On Wed, Jun 23, 2021 at 10:46:25AM -0400, min.li.xe@renesas.com wrote:

quoted

+static int idt82p33_start_ddco(struct idt82p33_channel *channel, s32
+delta_ns) {
+	s32 current_ppm = channel->current_freq;
+	u32 duration_ms = MSEC_PER_SEC;

What happens if user space makes a new adjustment before this completes?

After all, some PTP profiles update the clock several times per second.

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 *ptp, s64 delta_ns)
 	struct idt82p33 *idt82p33 = channel->idt82p33;
 	int err;
 
+	if (channel->ddco == true)
+		return 0;
+