Re: [PATCH net-next 3/5] net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function
From: Richard Cochran
Date: Wed May 29 2019 - 00:52:43 EST
On Wed, May 29, 2019 at 02:56:25AM +0300, Vladimir Oltean wrote:
> The newly introduced function is called on both the RX and TX paths.
NAK on this patch.
> The boolean returned by port_txtstamp should only return false if the
> driver tried to timestamp the skb but failed.
So you say.
> Currently there is some logic in the mv88e6xxx driver that determines
> whether it should timestamp frames or not.
>
> This is wasteful, because if the decision is to not timestamp them, then
> DSA will have cloned an skb and freed it immediately afterwards.
No, it isn't wasteful. Look at the tests in that driver to see why.
> Additionally other drivers (sja1105) may have other hardware criteria
> for timestamping frames on RX, and the default conditions for
> timestamping a frame are too restrictive.
I'm sorry, but we won't change the frame just for one device that has
design issues.
Please put device specific workarounds into its driver.
Thanks,
Richard