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Message-ID: <20201101020227.GB2683@hoboy.vegasvil.org>
Date: Sat, 31 Oct 2020 19:02:27 -0700
From: Richard Cochran <richardcochran@...il.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Grygorii Strashko <grygorii.strashko@...com>,
"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Vignesh Raghavendra <vigneshr@...com>,
Sekhar Nori <nsekhar@...com>, linux-kernel@...r.kernel.org,
linux-omap@...r.kernel.org
Subject: Re: [PATCH] net: ethernet: ti: cpsw: disable PTPv1 hw timestamping
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On Sat, Oct 31, 2020 at 11:40:42AM -0700, Jakub Kicinski wrote:
> On Thu, 29 Oct 2020 21:09:10 +0200 Grygorii Strashko wrote:
> > The TI CPTS does not natively support PTPv1, only PTPv2. But, as it
> > happens, the CPTS can provide HW timestamp for PTPv1 Sync messages, because
> > CPTS HW parser looks for PTP messageType id in PTP message octet 0 which
> > value is 0 for PTPv1. As result, CPTS HW can detect Sync messages for PTPv1
> > and PTPv2 (Sync messageType = 0 for both), but it fails for any other PTPv1
> > messages (Delay_req/resp) and will return PTP messageType id 0 for them.
> >
> > The commit e9523a5a32a1 ("net: ethernet: ti: cpsw: enable
> > HWTSTAMP_FILTER_PTP_V1_L4_EVENT filter") added PTPv1 hw timestamping
> > advertisement by mistake, only to make Linux Kernel "timestamping" utility
> > work, and this causes issues with only PTPv1 compatible HW/SW - Sync HW
> > timestamped, but Delay_req/resp are not.
> >
> > Hence, fix it disabling PTPv1 hw timestamping advertisement, so only PTPv1
> > compatible HW/SW can properly roll back to SW timestamping.
> >
> > Fixes: e9523a5a32a1 ("net: ethernet: ti: cpsw: enable HWTSTAMP_FILTER_PTP_V1_L4_EVENT filter")
> > Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
>
> CC: Richard
Acked-by: Richard Cochran <richardcochran@...il.com>
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