From: Ahmed S. Darwish <ahmed.darw...@valeo.com>

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 <ahmed.darw...@valeo.com>
---
 drivers/net/can/usb/kvaser_usb.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
index 55407b9..7af379c 100644
--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -698,9 +698,7 @@ 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;
@@ -710,7 +708,8 @@ 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;
 
-- 
1.7.7.6

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