Patch "can: kvaser_usb_leaf: Set Warning state even without bus errors" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    can: kvaser_usb_leaf: Set Warning state even without bus errors

to the 4.19-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-kvaser_usb_leaf-set-warning-state-even-without-b.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3148f8b7230ac5412b756150dc8d2994e248787a
Author: Anssi Hannula <anssi.hannula@xxxxxxxxxx>
Date:   Mon Oct 10 20:52:31 2022 +0200

    can: kvaser_usb_leaf: Set Warning state even without bus errors
    
    [ Upstream commit df1b7af2761b935f63b4a53e789d41ed859edf61 ]
    
    kvaser_usb_leaf_rx_error_update_can_state() sets error state according
    to error counters when the hardware does not indicate a specific state
    directly.
    
    However, this is currently gated behind a check for
    M16C_STATE_BUS_ERROR which does not always seem to be set when error
    counters are increasing, and may not be set when error counters are
    decreasing.
    
    This causes the CAN_STATE_ERROR_WARNING state to not be set in some
    cases even when appropriate.
    
    Change the code to set error state from counters even without
    M16C_STATE_BUS_ERROR.
    
    The Error-Passive case seems superfluous as it is already set via
    M16C_STATE_BUS_PASSIVE flag above, but it is kept for now.
    
    Tested with 0bfd:0124 Kvaser Mini PCI Express 2xHS FW 4.18.778.
    
    Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
    Tested-by: Jimmy Assarsson <extja@xxxxxxxxxx>
    Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxxxxxx>
    Signed-off-by: Jimmy Assarsson <extja@xxxxxxxxxx>
    Link: https://lore.kernel.org/all/20221010185237.319219-6-extja@xxxxxxxxxx
    Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
index 3c3e78992b55..b43631eaccf1 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -965,20 +965,16 @@ kvaser_usb_leaf_rx_error_update_can_state(struct kvaser_usb_net_priv *priv,
 		new_state = CAN_STATE_BUS_OFF;
 	} else if (es->status & M16C_STATE_BUS_PASSIVE) {
 		new_state = CAN_STATE_ERROR_PASSIVE;
-	} else if (es->status & M16C_STATE_BUS_ERROR) {
+	} else if ((es->status & M16C_STATE_BUS_ERROR) &&
+		   cur_state >= CAN_STATE_BUS_OFF) {
 		/* Guard against spurious error events after a busoff */
-		if (cur_state < CAN_STATE_BUS_OFF) {
-			if (es->txerr >= 128 || es->rxerr >= 128)
-				new_state = CAN_STATE_ERROR_PASSIVE;
-			else if (es->txerr >= 96 || es->rxerr >= 96)
-				new_state = CAN_STATE_ERROR_WARNING;
-			else if (cur_state > CAN_STATE_ERROR_ACTIVE)
-				new_state = CAN_STATE_ERROR_ACTIVE;
-		}
-	}
-
-	if (!es->status)
+	} else if (es->txerr >= 128 || es->rxerr >= 128) {
+		new_state = CAN_STATE_ERROR_PASSIVE;
+	} else if (es->txerr >= 96 || es->rxerr >= 96) {
+		new_state = CAN_STATE_ERROR_WARNING;
+	} else {
 		new_state = CAN_STATE_ERROR_ACTIVE;
+	}
 
 	if (new_state != cur_state) {
 		tx_state = (es->txerr >= es->rxerr) ? new_state : 0;