This is a note to let you know that I've just added the patch titled can: esd_usb: Allow REC and TEC to return to zero to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: can-esd_usb-allow-rec-and-tec-to-return-to-zero.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 9fe59188408f1effccc891decb36be4ec08fcd71 Author: Frank Jungclaus <frank.jungclaus@xxxxxx> Date: Wed Nov 30 21:22:42 2022 +0100 can: esd_usb: Allow REC and TEC to return to zero [ Upstream commit 918ee4911f7a41fb4505dff877c1d7f9f64eb43e ] We don't get any further EVENT from an esd CAN USB device for changes on REC or TEC while those counters converge to 0 (with ecc == 0). So when handling the "Back to Error Active"-event force txerr = rxerr = 0, otherwise the berr-counters might stay on values like 95 forever. Also, to make life easier during the ongoing development a netdev_dbg() has been introduced to allow dumping error events send by an esd CAN USB device. Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device") Signed-off-by: Frank Jungclaus <frank.jungclaus@xxxxxx> Link: https://lore.kernel.org/all/20221130202242.3998219-2-frank.jungclaus@xxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/can/usb/esd_usb2.c b/drivers/net/can/usb/esd_usb2.c index 8847942a8d97..73c5343e609b 100644 --- a/drivers/net/can/usb/esd_usb2.c +++ b/drivers/net/can/usb/esd_usb2.c @@ -227,6 +227,10 @@ static void esd_usb2_rx_event(struct esd_usb2_net_priv *priv, u8 rxerr = msg->msg.rx.data[2]; u8 txerr = msg->msg.rx.data[3]; + netdev_dbg(priv->netdev, + "CAN_ERR_EV_EXT: dlc=%#02x state=%02x ecc=%02x rec=%02x tec=%02x\n", + msg->msg.rx.dlc, state, ecc, rxerr, txerr); + skb = alloc_can_err_skb(priv->netdev, &cf); if (skb == NULL) { stats->rx_dropped++; @@ -253,6 +257,8 @@ static void esd_usb2_rx_event(struct esd_usb2_net_priv *priv, break; default: priv->can.state = CAN_STATE_ERROR_ACTIVE; + txerr = 0; + rxerr = 0; break; } } else {