Re: [PATCH v3] can: peak_usb: Add PCAN-USB bus errors reporting

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] can: missing CAN_ERR_CNT flag in bus error frame
--

commit d66a7ddeb9e61cb6f2f338731231a0a8c41a3d91
Author: Stéphane Grosjean <s.grosjean@peak-system.fr>

can: peak_usb: Add PCAN-USB bus errors reporting

This patch implements missing CAN bus error reporting for PCAN-USB devices.
It parses the hardware ECC, RX, and TX counters to construct standard CAN
error frames.

> diff --git a/drivers/net/can/usb/peak_usb/pcan_usb.c b/drivers/net/can/usb/peak_usb/pcan_usb.c
> index 8fd058c328564..c59166a29648d 100644
> --- a/drivers/net/can/usb/peak_usb/pcan_usb.c
> +++ b/drivers/net/can/usb/peak_usb/pcan_usb.c
[ ... ]
> @@ -550,23 +560,94 @@ static int pcan_usb_decode_error(struct pcan_usb_msg_context *mc, u8 n,
[ ... ]
> +			/* allocate an skb to store the error frame */
> +			skb = alloc_can_err_skb(mc->netdev, &cf);
> +			if (!skb)
> +				return -ENOMEM;
> +
> +			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +			cf->data[2] |= can_err_tx;
> +
> +			/* set error type according to 1st data byte (ECC) */
[ ... ]
> +			/* set error location */
> +			cf->data[3] = ecc & PCAN_SJA1000_ECC_SEG;
> +
> +			cf->data[6] = pdev->bec.txerr;
> +			cf->data[7] = pdev->bec.rxerr;

[Severity: Medium]
Is this missing the CAN_ERR_CNT flag in cf->can_id?

Userspace tools like candump rely on the CAN_ERR_CNT flag in the CAN ID to
know if data[6] and data[7] contain valid error counters. Because the flag
is not set here in pcan_usb_handle_bus_evt(), will these tools silently
ignore the newly provided TX and RX error counters?

> +
> +			if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
> +				struct skb_shared_hwtstamps *hwts =
> +					skb_hwtstamps(skb);
> +
> +				peak_usb_get_ts_time(&mc->pdev->time_ref,
> +						     mc->ts16, &hwts->hwtstamp);
> +			}
> +
> +			netif_rx(skb);
> +		}
>  	}
>  
>  	return 0;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260925-peak_usb-v3-1-e7bfccacf795@peak-system.fr?part=1