[PATCH can-next 1/7] can: peak_usb: fix missing CAN_ERR_FLAG when reporting error counters

From: Marc Kleine-Budde

Date: Fri Oct 02 2026 - 04:16:23 EST


From: Stefan Günther <stefangun@xxxxx>

When the device reports error counters, the driver incorrectly uses an
assignment (=) instead of a bitwise OR (|=) for CAN_ERR_CNT. This wipes
out the CAN_ERR_FLAG and CAN_ERR_CRTL flags, causing the error frame to
be sent to userspace as a regular CAN frame with ID 0x200.

Fix this by using a bitwise OR to preserve the flags.

Signed-off-by: Stefan Günther <stefangun@xxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 3e5c291c7942 ("can: add CAN_ERR_CNT flag to notify availability of error counter")
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/usb/peak_usb/pcan_usb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/peak_usb/pcan_usb.c b/drivers/net/can/usb/peak_usb/pcan_usb.c
index 8fd058c32856..785224e00c4e 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb.c
@@ -526,7 +526,7 @@ static int pcan_usb_decode_error(struct pcan_usb_msg_context *mc, u8 n,
/* Supply TX/RX error counters in case of
* controller error.
*/
- cf->can_id = CAN_ERR_CNT;
+ cf->can_id |= CAN_ERR_CNT;
cf->data[6] = mc->pdev->bec.txerr;
cf->data[7] = mc->pdev->bec.rxerr;
}

--
2.53.0