From 00293f362712b791b5d6489def51889c13b7ec17 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Thu, 19 Feb 2026 13:57:34 +0100 Subject: [PATCH] can: gs_usb: gs_can_open(): always configure bitrates before starting device commit 2df6162785f31f1bbb598cfc3b08e4efc88f80b6 upstream. So far the driver populated the struct can_priv::do_set_bittiming() and struct can_priv::fd::do_set_data_bittiming() callbacks. Before bringing up the interface, user space has to configure the bitrates. With these callbacks the configuration is directly forwarded into the CAN hardware. Then the interface can be brought up. An ifdown-ifup cycle (without changing the bit rates) doesn't re-configure the bitrates in the CAN hardware. This leads to a problem with the CANable-2.5 [1] firmware, which resets the configured bit rates during ifdown. To fix the problem remove both bit timing callbacks and always configure the bitrates in the struct net_device_ops::ndo_open() callback. [1] https://github.com/Elmue/CANable-2.5-firmware-Slcan-and-Candlelight Cc: stable@vger.kernel.org Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices") Link: https://patch.msgid.link/20260219-gs_usb-always-configure-bitrates-v2-1-671f8ba5b0a5@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/usb/gs_usb.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index 861b58393522..e336703b941e 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -772,9 +772,8 @@ device_detach: } } -static int gs_usb_set_bittiming(struct net_device *netdev) +static int gs_usb_set_bittiming(struct gs_can *dev) { - struct gs_can *dev = netdev_priv(netdev); struct can_bittiming *bt = &dev->can.bittiming; struct gs_device_bittiming dbt = { .prop_seg = cpu_to_le32(bt->prop_seg), @@ -791,9 +790,8 @@ static int gs_usb_set_bittiming(struct net_device *netdev) GFP_KERNEL); } -static int gs_usb_set_data_bittiming(struct net_device *netdev) +static int gs_usb_set_data_bittiming(struct gs_can *dev) { - struct gs_can *dev = netdev_priv(netdev); struct can_bittiming *bt = &dev->can.fd.data_bittiming; struct gs_device_bittiming dbt = { .prop_seg = cpu_to_le32(bt->prop_seg), @@ -1057,6 +1055,20 @@ static int gs_can_open(struct net_device *netdev) if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) flags |= GS_CAN_MODE_HW_TIMESTAMP; + rc = gs_usb_set_bittiming(dev); + if (rc) { + netdev_err(netdev, "failed to set bittiming: %pe\n", ERR_PTR(rc)); + goto out_usb_kill_anchored_urbs; + } + + if (ctrlmode & CAN_CTRLMODE_FD) { + rc = gs_usb_set_data_bittiming(dev); + if (rc) { + netdev_err(netdev, "failed to set data bittiming: %pe\n", ERR_PTR(rc)); + goto out_usb_kill_anchored_urbs; + } + } + /* finally start device */ dev->can.state = CAN_STATE_ERROR_ACTIVE; dm.flags = cpu_to_le32(flags); @@ -1357,7 +1369,6 @@ static struct gs_can *gs_make_candev(unsigned int channel, dev->can.state = CAN_STATE_STOPPED; dev->can.clock.freq = le32_to_cpu(bt_const.fclk_can); dev->can.bittiming_const = &dev->bt_const; - dev->can.do_set_bittiming = gs_usb_set_bittiming; dev->can.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC; @@ -1381,7 +1392,6 @@ static struct gs_can *gs_make_candev(unsigned int channel, * GS_CAN_FEATURE_BT_CONST_EXT is set. */ dev->can.fd.data_bittiming_const = &dev->bt_const; - dev->can.fd.do_set_data_bittiming = gs_usb_set_data_bittiming; } if (feature & GS_CAN_FEATURE_TERMINATION) {