>
> MAC address having to be unique, a MAC coming from the host
> must be used at most once at a time. Hence the users must
> be recorded and additional users must fall back to conventional
> methods.
I checked with the internal team and actually applies pass through MAC on both
Windows Realtek driver and in UEFI network stack this applies to ALL supported
Realtek devices (R8153-AD).
>
> Signed-off-by: Oliver Neukum <oneu...@suse.com>
> Fixes: 34ee32c9a5696 ("r8152: Add support for setting pass through MAC
> address on
> RTL8153-AD")
> ---
> drivers/net/usb/r8152.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index f1b5201cc320..7345a2258ee4 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -766,6 +766,9 @@ enum tx_csum_stat {
> TX_CSUM_NONE
> };
>
> +/* pass through MACs are per host, hence concurrent use is forbidden */
> +static struct r8152 *pass_through_user = NULL;
> +
> /* Maximum number of multicast addresses to filter (vs. Rx-all-multicast).
> * The RTL chips use a 64 element hash table based on the Ethernet CRC.
> */
> @@ -1221,7 +1224,14 @@ static int set_ethernet_addr(struct r8152 *tp)
> * or system doesn't provide valid _SB.AMAC this will be
> * be expected to non-zero
> */
> - ret = vendor_mac_passthru_addr_read(tp, &sa);
> + if (!pass_through_user) {
> + ret = vendor_mac_passthru_addr_read(tp, &sa);
> + if (ret >= 0)
> + /* we must record the user against concurrent
> use
> */
> + pass_through_user = tp;
> + } else {
> + ret = -EBUSY;
> + }
> if (ret < 0)
> ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data);
> }
> @@ -5304,6 +5314,8 @@ static void rtl8152_disconnect(struct usb_interface
> *intf)
> cancel_delayed_work_sync(&tp->hw_phy_work);
> tp->rtl_ops.unload(tp);
> free_netdev(tp->netdev);
> + if (pass_through_user == tp)
> + pass_through_user = NULL;
> }
> }
>
> --
> 2.16.4
