Le 08/13/15 21:23, shh....@gmail.com a écrit :
> From: Shaohui Xie <shaohui....@freescale.com>
>
> Currently, if phy state is PHY_RUNNING, we always register a CHANGE
> when phy works in polling or interrupt ignored, this will make the
> adjust_link being called even the phy link did Not changed.
Right, which is why most drivers do implement a caching scheme.
>
> checking the phy link to make sure the link did changed before we
> register a CHANGE, if link did not changed, we do nothing.
With your change we will end-up with virtually polling a PHY twice as
fast as we used to with the RUNNING -> CHANGELINK -> RUNNING transition
(current state transitions), which is probably fine, but puts a bit more
pressure on the (slow) MDIO bus since we end-up with two additional
reads to latch the link status register.
PS: I would appreciate if you could CC me on future libphy submissions.
>
> Signed-off-by: Shaohui Xie <shaohui....@freescale.com>
> ---
> drivers/net/phy/phy.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index 84b1fba..d972851 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -814,6 +814,7 @@ void phy_state_machine(struct work_struct *work)
> bool needs_aneg = false, do_suspend = false;
> enum phy_state old_state;
> int err = 0;
> + int old_link;
>
> mutex_lock(&phydev->lock);
>
> @@ -899,11 +900,18 @@ void phy_state_machine(struct work_struct *work)
> phydev->adjust_link(phydev->attached_dev);
> break;
> case PHY_RUNNING:
> - /* Only register a CHANGE if we are
> - * polling or ignoring interrupts
> + /* Only register a CHANGE if we are polling or ignoring
> + * interrupts and link changed since latest checking.
> */
> - if (!phy_interrupt_is_valid(phydev))
> - phydev->state = PHY_CHANGELINK;
> + if (!phy_interrupt_is_valid(phydev)) {
> + old_link = phydev->link;
> + err = phy_read_status(phydev);
> + if (err)
> + break;
> +
> + if (old_link != phydev->link)
> + phydev->state = PHY_CHANGELINK;
> + }
> break;
> case PHY_CHANGELINK:
> err = phy_read_status(phydev);
>
--
Florian
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