linux-kernel - Re: [PATCH 2/3] can: esd_usb: Improved behavior on esd CAN_ERROR

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Date:   Tue, 20 Dec 2022 14:49:29 +0900
From:   Vincent MAILHOL <mailhol.vincent@...adoo.fr>
To:     Frank Jungclaus <frank.jungclaus@....eu>
Cc:     linux-can@...r.kernel.org, Marc Kleine-Budde <mkl@...gutronix.de>,
        Wolfgang Grandegger <wg@...ndegger.com>,
        Stefan Mätje <stefan.maetje@....eu>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] can: esd_usb: Improved behavior on esd CAN_ERROR_EXT
 event (2)

On Tue. 20 Dec. 2022 at 06:29, Frank Jungclaus <frank.jungclaus@....eu> wrote:
> Started a rework initiated by Vincents remarks "You should not report
> the greatest of txerr and rxerr but the one which actually increased."
> [1]

I do not see this comment being addressed. You are still assigning the
flags depending on the highest value, not the one which actually
changed.

> and "As far as I understand, those flags should be set only when
> the threshold is *reached*" [2] .
>
> Now setting the flags for CAN_ERR_CRTL_[RT]X_WARNING and
> CAN_ERR_CRTL_[RT]X_PASSIVE regarding REC and TEC, when the
> appropriate threshold is reached.
>
> Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device")
> Signed-off-by: Frank Jungclaus <frank.jungclaus@....eu>
> Link: [1] https://lore.kernel.org/all/CAMZ6RqKGBWe15aMkf8-QLf-cOQg99GQBebSm+1wEzTqHgvmNuw@mail.gmail.com/
> Link: [2] https://lore.kernel.org/all/CAMZ6Rq+QBO1yTX_o6GV0yhdBj-RzZSRGWDZBS0fs7zbSTy4hmA@mail.gmail.com/
> ---
>  drivers/net/can/usb/esd_usb.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
> index 5e182fadd875..09745751f168 100644
> --- a/drivers/net/can/usb/esd_usb.c
> +++ b/drivers/net/can/usb/esd_usb.c
> @@ -255,10 +255,18 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
>                                 can_bus_off(priv->netdev);
>                                 break;
>                         case ESD_BUSSTATE_WARN:
> +                               cf->can_id |= CAN_ERR_CRTL;
> +                               cf->data[1] = (txerr > rxerr) ?
> +                                               CAN_ERR_CRTL_TX_WARNING :
> +                                               CAN_ERR_CRTL_RX_WARNING;

Nitpick: when a ternary operator is too long to fit on one line,
prefer an if/else.

>                                 priv->can.state = CAN_STATE_ERROR_WARNING;
>                                 priv->can.can_stats.error_warning++;
>                                 break;
>                         case ESD_BUSSTATE_ERRPASSIVE:
> +                               cf->can_id |= CAN_ERR_CRTL;
> +                               cf->data[1] = (txerr > rxerr) ?
> +                                               CAN_ERR_CRTL_TX_PASSIVE :
> +                                               CAN_ERR_CRTL_RX_PASSIVE;

Same.

>                                 priv->can.state = CAN_STATE_ERROR_PASSIVE;
>                                 priv->can.can_stats.error_passive++;
>                                 break;
> @@ -296,12 +304,6 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
>                         /* Bit stream position in CAN frame as the error was detected */
>                         cf->data[3] = ecc & SJA1000_ECC_SEG;
>
> -                       if (priv->can.state == CAN_STATE_ERROR_WARNING ||
> -                           priv->can.state == CAN_STATE_ERROR_PASSIVE) {
> -                               cf->data[1] = (txerr > rxerr) ?
> -                                       CAN_ERR_CRTL_TX_PASSIVE :
> -                                       CAN_ERR_CRTL_RX_PASSIVE;
> -                       }
>                         cf->data[6] = txerr;
>                         cf->data[7] = rxerr;
>                 }

Yours sincerely,
Vincent Mailhol