Re: [PATCH v2 2/3] can: cc770: Stop queue on NETDEV_TX_BUSY

[Richard Weinberger <richard@sigma-star.at>]

Andri,

Am Dienstag, 30. Januar 2018, 17:56:48 CET schrieb Andri Yngvason:
> If the queue is not stopped, the start_xmit function will continue to be
> called until the driver or the system is reset.
> 
> Signed-off-by: Andri Yngvason <andri.yngvason@marel.com>
> ---
>  drivers/net/can/cc770/cc770.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c
> index 9fed163..12d3b89 100644
> --- a/drivers/net/can/cc770/cc770.c
> +++ b/drivers/net/can/cc770/cc770.c
> @@ -405,6 +405,7 @@ static netdev_tx_t cc770_start_xmit(struct sk_buff *skb,
> struct net_device *dev)
> 
>  	if ((cc770_read_reg(priv,
>  			    msgobj[mo].ctrl1) & TXRQST_UNC) == TXRQST_SET) {
> +		netif_stop_queue(dev);
>  		netdev_err(dev, "TX register is still occupied!\n");
>  		return NETDEV_TX_BUSY;
>  	}

I see that some can drivers stop the queue, others not.
What exactly is the problem in this case?

Thanks,
//richard

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