Re: [PATCH v2 net] net: stmmac: retain PTP clock time during SIOCSHWTSTAMP ioctls

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller [off-list ref]:

On Sun, 21 Nov 2021 19:57:04 +0200 you wrote:

From: Holger Assmann <redacted>

Currently, when user space emits SIOCSHWTSTAMP ioctl calls such as
enabling/disabling timestamping or changing filter settings, the driver
reads the current CLOCK_REALTIME value and programming this into the
NIC's hardware clock. This might be necessary during system
initialization, but at runtime, when the PTP clock has already been
synchronized to a grandmaster, a reset of the timestamp settings might
result in a clock jump. Furthermore, if the clock is also controlled by
phc2sys in automatic mode (where the UTC offset is queried from ptp4l),
that UTC-to-TAI offset (currently 37 seconds in 2021) would be
temporarily reset to 0, and it would take a long time for phc2sys to
readjust so that CLOCK_REALTIME and the PHC are apart by 37 seconds
again.

[...]

Here is the summary with links:
  - [v2,net] net: stmmac: retain PTP clock time during SIOCSHWTSTAMP ioctls
    https://git.kernel.org/netdev/net/c/a6da2bbb0005

You are awesome, thank you!
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