On 2024-07-10 at 01:28:45, Ronald Wahl (rwahl@xxxxxx) wrote:
> From: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
>
> The amount of TX space in the hardware buffer is tracked in the tx_space
> variable. The initial value is currently only set during driver probing.
>
> After closing the interface and reopening it the tx_space variable has
> the last value it had before close. If it is smaller than the size of
> the first send packet after reopeing the interface the queue will be
> stopped. The queue is woken up after receiving a TX interrupt but this
> will never happen since we did not send anything.
>
> This commit moves the initialization of the tx_space variable to the
> ks8851_net_open function right before starting the TX queue. Also query
> the value from the hardware instead of using a hard coded value.
>
> Only the SPI chip variant is affected by this issue because only this
> driver variant actually depends on the tx_space variable in the xmit
> function.
>
> Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun")
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: Simon Horman <horms@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx # 5.10+
> Signed-off-by: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
> ---
> drivers/net/ethernet/micrel/ks8851_common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c
> index 6453c92f0fa7..03a554df6e7a 100644
> --- a/drivers/net/ethernet/micrel/ks8851_common.c
> +++ b/drivers/net/ethernet/micrel/ks8851_common.c
> @@ -482,6 +482,7 @@ static int ks8851_net_open(struct net_device *dev)
> ks8851_wrreg16(ks, KS_IER, ks->rc_ier);
>
> ks->queued_len = 0;
> + ks->tx_space = ks8851_rdreg16(ks, KS_TXMIR);
> netif_start_queue(ks->netdev);
>
> netif_dbg(ks, ifup, ks->netdev, "network device up\n");
> @@ -1101,7 +1102,6 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
> int ret;
>
> ks->netdev = netdev;
> - ks->tx_space = 6144;
>
> ks->gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> ret = PTR_ERR_OR_ZERO(ks->gpio);
> --
> 2.45.2
>
>
Reviewed-by: Hariprasad Kelam <hkelam@xxxxxxxxxxx>
