2022-07-08 18:15:48

by Frank Jungclaus

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Subject: [PATCH 4/6] can: esd_usb: Improved behavior on esd CAN_ERROR_EXT event (3)

Started a rework initiated by Vincents remark about "You should not
report the greatest of txerr and rxerr but the one which actually
increased." Now setting CAN_ERR_CRTL_[RT]X_WARNING and
CAN_ERR_CRTL_[RT]X_PASSIVE depending on REC and TEC

Signed-off-by: Frank Jungclaus <[email protected]>
---
drivers/net/can/usb/esd_usb.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 0a402a23d7ac..588caba1453b 100644
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -304,11 +304,17 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
/* Store error in CAN protocol (location) in data[3] */
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;
+ /* Store error status of CAN-controller in data[1] */
+ if (priv->can.state == CAN_STATE_ERROR_WARNING) {
+ if (txerr >= 96)
+ cf->data[1] |= CAN_ERR_CRTL_TX_WARNING;
+ if (rxerr >= 96)
+ cf->data[1] |= CAN_ERR_CRTL_RX_WARNING;
+ } else if (priv->can.state == CAN_STATE_ERROR_PASSIVE) {
+ if (txerr >= 128)
+ cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
+ if (rxerr >= 128)
+ cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
}

cf->data[6] = txerr;
--
2.25.1


2022-07-12 14:52:28

by Vincent MAILHOL

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Subject: Re: [PATCH 4/6] can: esd_usb: Improved behavior on esd CAN_ERROR_EXT event (3)

On Tue. 9 Jul. 2022 at 03:15, Frank Jungclaus <[email protected]> wrote:
> Started a rework initiated by Vincents remark about "You should not
> report the greatest of txerr and rxerr but the one which actually
> increased." Now setting CAN_ERR_CRTL_[RT]X_WARNING and
> CAN_ERR_CRTL_[RT]X_PASSIVE depending on REC and TEC
>
> Signed-off-by: Frank Jungclaus <[email protected]>
> ---
> drivers/net/can/usb/esd_usb.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
> index 0a402a23d7ac..588caba1453b 100644
> --- a/drivers/net/can/usb/esd_usb.c
> +++ b/drivers/net/can/usb/esd_usb.c
> @@ -304,11 +304,17 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
> /* Store error in CAN protocol (location) in data[3] */
> 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;
> + /* Store error status of CAN-controller in data[1] */
> + if (priv->can.state == CAN_STATE_ERROR_WARNING) {
> + if (txerr >= 96)
> + cf->data[1] |= CAN_ERR_CRTL_TX_WARNING;

As far as I understand, those flags should be set only when the
threshold is *reached*:
https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/can/error.h#L69

I don't think you should set it if the error state does not change.

Here, you probably want to compare the new value with the previous
one (stored in struct can_berr_counter) to decide whether or not the
flags should be set.


> + if (rxerr >= 96)
> + cf->data[1] |= CAN_ERR_CRTL_RX_WARNING;
> + } else if (priv->can.state == CAN_STATE_ERROR_PASSIVE) {
> + if (txerr >= 128)
> + cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
> + if (rxerr >= 128)
> + cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
> }
>
> cf->data[6] = txerr;
> --
> 2.25.1
>

2022-07-12 16:37:23

by Frank Jungclaus

[permalink] [raw]
Subject: Re: [PATCH 4/6] can: esd_usb: Improved behavior on esd CAN_ERROR_EXT event (3)

On Tue, 2022-07-12 at 23:39 +0900, Vincent MAILHOL wrote:
> On Tue. 9 Jul. 2022 at 03:15, Frank Jungclaus <[email protected]> wrote:
> > Started a rework initiated by Vincents remark about "You should not
> > report the greatest of txerr and rxerr but the one which actually
> > increased." Now setting CAN_ERR_CRTL_[RT]X_WARNING and
> > CAN_ERR_CRTL_[RT]X_PASSIVE depending on REC and TEC
> >
> > Signed-off-by: Frank Jungclaus <[email protected]>
> > ---
> > drivers/net/can/usb/esd_usb.c | 16 +++++++++++-----
> > 1 file changed, 11 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
> > index 0a402a23d7ac..588caba1453b 100644
> > --- a/drivers/net/can/usb/esd_usb.c
> > +++ b/drivers/net/can/usb/esd_usb.c
> > @@ -304,11 +304,17 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
> > /* Store error in CAN protocol (location) in data[3] */
> > 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;
> > + /* Store error status of CAN-controller in data[1] */
> > + if (priv->can.state == CAN_STATE_ERROR_WARNING) {
> > + if (txerr >= 96)
> > + cf->data[1] |= CAN_ERR_CRTL_TX_WARNING;
>
> As far as I understand, those flags should be set only when the
> threshold is *reached*:
> https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/can/error.h#L69
>
> I don't think you should set it if the error state does not change.
>
> Here, you probably want to compare the new value with the previous
> one (stored in struct can_berr_counter) to decide whether or not the
> flags should be set.

Hi Vincent, I didn't interpret the comments given to data[1] in error.h
in that way (obviously). But after checking some other drivers, I see
they all seem to handle it the way you proposed it ...
So, I'll try to rework and resend patch 4/6, too.

Best regards,
Frank

>
>
> > + if (rxerr >= 96)
> > + cf->data[1] |= CAN_ERR_CRTL_RX_WARNING;
> > + } else if (priv->can.state == CAN_STATE_ERROR_PASSIVE) {
> > + if (txerr >= 128)
> > + cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
> > + if (rxerr >= 128)
> > + cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
> > }
> >
> > cf->data[6] = txerr;
> > --
> > 2.25.1
> >