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Message-ID: <20080703162428.55d9f345@extreme>
Date: Thu, 3 Jul 2008 16:24:28 -0700
From: Stephen Hemminger <shemminger@...tta.com>
To: Octavian Purdila <opurdila@...acom.com>
Cc: netdev@...r.kernel.org
Subject: Re: [RFC] support for IEEE 1588
On Fri, 4 Jul 2008 01:47:11 +0300
Octavian Purdila <opurdila@...acom.com> wrote:
>
> Hi everybody,
>
> IEEE 1588 Precision Time Protocol [1] requires hardware timestamping support
> for both RX and TX frames. It seems that in Linux we do not have the support
> required for this protocol to be implemented.
>
> Any feedback on the approach we are planing to take is greatly appreciated. We
> will follow with a patch at some point, but I just want to check with you
> gurus early, to avoid potential design flaws. If a patch is preferred for
> commenting on, then please ignore this and will come back later with the
> patch.
>
> 1. RX path
> - add a new field in skb to keep the hardware stamp (hwstamp)
> - add a new socket flag to enable RX stamping
> - add a new control message to retrieve the hwstamp from the skb to user-space
> application (for UDP and maybe PF_PACKET)
The existing skb timestamp is there, and if the hardware supports it, it could
be updated by the device driver I had a version of sky2 that did just that
but never fully pushed it upstream because of available time and testing issues.
The API's are already there (and used) for timestamping; don't invent
new ones.
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