Re: [PATCH net-next v5 2/8] net: phy: phylink: add helper to modify pause

[Maxime Chevallier]

Hi, 

On 7/7/26 11:16, javen wrote:
> From: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
> 
> For Realtek nics, when we enable jumbo, pause are not supported. So we
> must check the pause capabilities from ourself and lp.
> 
> Signed-off-by: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
> ---
> Changes in v5:
>  - no changes, new file
> ---
>  drivers/net/phy/phylink.c | 66 +++++++++++++++++++++++++++++++++++++++
>  include/linux/phylink.h   |  2 ++
>  2 files changed, 68 insertions(+)
> 
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index 59dfe35afa54..c450ee33b75c 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -1828,6 +1828,72 @@ int phylink_set_fixed_link(struct phylink *pl,
>  }
>  EXPORT_SYMBOL_GPL(phylink_set_fixed_link);
>  
> +/**
> + * phylink_set_mac_capabilities() - Dynamically update MAC capabilities
> + * @pl: a pointer to a &struct phylink returned from phylink_create()
> + * @mac_capabilities: the new MAC capabilities mask
> + *
> + * This function allows a MAC driver to dynamically change its capabilities,
> + * such as losing/gaining Pause frame support based on MTU size.
> + * It recalculates supported link modes and triggers renegotiation if needed.
> + */
> +void phylink_set_mac_capabilities(struct phylink *pl, unsigned long mac_capabilities)

This is a step in the right direction, but this is maybe too generic, as
mac_capabilities represent both the MAC's Pause support as well as Speed/Duplex
support.

The speed/duplex parts shouldn't be changed dynamically, I think the helper
needs to be specific in its naming that this is strictly about changing the MAC's
Pause / Asym capabilities dynamically, and be either passed some booleans, one for
rx one for tx, or fail if we try to change anything other than MAC_SYM_PAUSE and
MAC_ASYM_PAUSE.

Maybe something like "phylink_update_mac_pause_capabilities" ?

The 'update' part makes it clear this may trigger re-negotiation.


Maxime