Re: CM-ITC, pch_can/c_can_pci, sendto() returning ENOBUFS

[Jacob Kroon <jacob.kroon@gmail.com>]

Hi Dario,

On 9/23/22 19:55, dariobin@libero.it wrote:
> Hi Michael,
> 
>> Il 23/09/2022 13:36 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:
>>
>>   
>> On 16.09.2022 06:14:58, Jacob Kroon wrote:
>>> What I do know is that if I revert commit:
>>>
>>> "can: c_can: cache frames to operate as a true FIFO"
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=387da6bc7a826cc6d532b1c0002b7c7513238d5f
>>>
>>> then everything looks good. I don't get any BUG messages, and the host
>>> has been running overnight without problems, so it seems to have fixed
>>> the network interface lockup as well.
>>
>> Jacob, after this mail, I'll send 2 patches. One tries to disable the
>> cache feature for C_CAN cores, the other shuts a potential race window.
> 
> About the "can: c_can: don't cache TX messages for C_CAN cores" patch:
> Could it make sense to change the c_can_start_xmit in this way
> 
> -       if (idx < c_can_get_tx_tail(tx_ring))
> -               cmd &= ~IF_COMM_TXRQST; /* Cache the message */
> +       if (idx < c_can_get_tx_tail(tx_ring)) {
> +               if (priv->type == BOSCH_D_CAN) {
> +                       cmd &= ~IF_COMM_TXRQST; /* Cache the message */
> +               } else {
> +                       netif_stop_queue(priv->dev);
> +                       return NETDEV_TX_BUSY;
> +               }
> +       }
> 
> without changing the c_can_get_tx_{free,busy} routines ?
> 

I can test, so you suggest only doing the above patch, or were there 
other parts from Marc's patch you wanted in ?

Jacob