From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Ahmed S. Darwish" , Marc Kleine-Budde , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 49/80] can: kvaser_usb: Fix state handling upon BUS_ERROR events Date: Thu, 19 Mar 2015 15:35:37 -0700 Message-Id: <1426804568-2907-50-git-send-email-kamal@canonical.com> In-Reply-To: <1426804568-2907-1-git-send-email-kamal@canonical.com> References: <1426804568-2907-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.13.11-ckt17 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Ahmed S. Darwish" commit e638642b08c170d2021b706f0b1c4f4ae93d8cbd upstream. While being in an ERROR_WARNING state, and receiving further bus error events with error counters still in the ERROR_WARNING range of 97-127 inclusive, the state handling code erroneously reverts back to ERROR_ACTIVE. Per the CAN standard, only revert to ERROR_ACTIVE when the error counters are less than 96. Moreover, in certain Kvaser models, the BUS_ERROR flag is always set along with undefined bits in the M16C status register. Thus use bitwise operators instead of full equality for checking that register against bus errors. Signed-off-by: Ahmed S. Darwish Signed-off-by: Marc Kleine-Budde Signed-off-by: Kamal Mostafa --- drivers/net/can/usb/kvaser_usb.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c index 5ea0de8..a3fb8b5 100644 --- a/drivers/net/can/usb/kvaser_usb.c +++ b/drivers/net/can/usb/kvaser_usb.c @@ -690,9 +690,7 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev, } new_state = CAN_STATE_ERROR_PASSIVE; - } - - if (status == M16C_STATE_BUS_ERROR) { + } else if (status & M16C_STATE_BUS_ERROR) { if ((priv->can.state < CAN_STATE_ERROR_WARNING) && ((txerr >= 96) || (rxerr >= 96))) { cf->can_id |= CAN_ERR_CRTL; @@ -702,7 +700,8 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev, priv->can.can_stats.error_warning++; new_state = CAN_STATE_ERROR_WARNING; - } else if (priv->can.state > CAN_STATE_ERROR_ACTIVE) { + } else if ((priv->can.state > CAN_STATE_ERROR_ACTIVE) && + ((txerr < 96) && (rxerr < 96))) { cf->can_id |= CAN_ERR_PROT; cf->data[2] = CAN_ERR_PROT_ACTIVE; -- 1.9.1