On Sun, Mar 24, 2019 at 04:02:43PM +0100, Heiner Kallweit wrote:
> This adds support for Fast Link Down as new PHY tunable.
> Fast Link Down reduces the time until a link down event is reported
> for 1000BaseT. According to the standard it's 750ms what is too long
> for several use cases.
>
> Signed-off-by: Heiner Kallweit <hkallwe...@gmail.com>
> ---
> include/uapi/linux/ethtool.h | 4 ++++
> net/core/ethtool.c | 2 ++
> 2 files changed, 6 insertions(+)
>
> diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
> index 3652b239d..2c7136adc 100644
> --- a/include/uapi/linux/ethtool.h
> +++ b/include/uapi/linux/ethtool.h
> @@ -252,9 +252,13 @@ struct ethtool_tunable {
> #define DOWNSHIFT_DEV_DEFAULT_COUNT 0xff
> #define DOWNSHIFT_DEV_DISABLE 0
>
> +#define ETHTOOL_PHY_FAST_LINK_DOWN_ON 0
> +#define ETHTOOL_PHY_FAST_LINK_DOWN_OFF 0xff
> +
> enum phy_tunable_id {
> ETHTOOL_PHY_ID_UNSPEC,
> ETHTOOL_PHY_DOWNSHIFT,
> + ETHTOOL_PHY_FAST_LINK_DOWN,
> /*
> * Add your fresh new phy tunable attribute above and remember to update
> * phy_tunable_strings[] in net/core/ethtool.c
It would be nice to have a short summary around here explaining how is
the value interpreted. While it's obvious from the second patch, one
shouldn't have to go into driver specific implementation to find out.
I also wonder if the range 0-254 ms is sufficient. Would it be possible
that there is some other hardware which would support e.g. 300 ms?
Michal Kubecek
> diff --git a/net/core/ethtool.c b/net/core/ethtool.c
> index b1eb32419..387d67eb7 100644
> --- a/net/core/ethtool.c
> +++ b/net/core/ethtool.c
> @@ -136,6 +136,7 @@ static const char
> phy_tunable_strings[__ETHTOOL_PHY_TUNABLE_COUNT][ETH_GSTRING_LEN] = {
> [ETHTOOL_ID_UNSPEC] = "Unspec",
> [ETHTOOL_PHY_DOWNSHIFT] = "phy-downshift",
> + [ETHTOOL_PHY_FAST_LINK_DOWN] = "phy-fast-link-down",
> };
>
> static int ethtool_get_features(struct net_device *dev, void __user
> *useraddr)
> @@ -2432,6 +2433,7 @@ static int ethtool_phy_tunable_valid(const struct
> ethtool_tunable *tuna)
> {
> switch (tuna->id) {
> case ETHTOOL_PHY_DOWNSHIFT:
> + case ETHTOOL_PHY_FAST_LINK_DOWN:
> if (tuna->len != sizeof(u8) ||
> tuna->type_id != ETHTOOL_TUNABLE_U8)
> return -EINVAL;
> --
> 2.21.0
>
>
