drivers/input/mouse/bcm5974.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-)
Mode switches sent before control response are ignored.
On receiving unknown 8-byte packets, assume that mode switch was ignored
and reset by switching to normal mode, waiting then switching back to
wellspring mode.
---
This patch addresses an issue where the bcm5974 driver switches modes
before the device is ready, resulting in an unresponsive trackpad and
"bcm5974: bad trackpad package, length: 8" repeated in logs.
Discussion of issue in the thread:
https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/
This fix is conservative, avoiding changing existing mode-switch
behavior because I cannot test all variations of hardware.
On receiving an unknown 8-byte packet, we assume the device is not in
wellspring mode and schedule an asynchronous mode reset.
Signed-off-by: Liam Mitchell <mitchell.liam@gmail.com>
Link: https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/
---
Changes in v2:
- mutex_lock -> guard(mutex)
- dprintk -> dev_err
- msleep -> fsleep
- removed 0 init
- cancel_work_sync -> disable_delayed_work_sync
- work_struct -> delayed_work
- Link to v1: https://lore.kernel.org/r/20260207-bcm5974-reset-v1-1-af7163903fa6@gmail.com
---
drivers/input/mouse/bcm5974.c | 40 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
index dfdfb59cc8b5..6ee766ed8402 100644
--- a/drivers/input/mouse/bcm5974.c
+++ b/drivers/input/mouse/bcm5974.c
@@ -286,6 +286,8 @@ struct bcm5974 {
const struct tp_finger *index[MAX_FINGERS]; /* finger index data */
struct input_mt_pos pos[MAX_FINGERS]; /* position array */
int slots[MAX_FINGERS]; /* slot assignments */
+ struct delayed_work mode_reset_work;
+ unsigned long last_mode_reset;
};
/* trackpad finger block data, le16-aligned */
@@ -696,6 +698,32 @@ static int bcm5974_wellspring_mode(struct bcm5974 *dev, bool on)
return retval;
}
+/*
+ * Mode switches sent before the control response are ignored.
+ * Fixing this state requires switching to normal mode and waiting
+ * about 1ms before switching back to wellspring mode.
+ */
+static void bcm5974_mode_reset_work(struct work_struct *work)
+{
+ int error;
+ struct bcm5974 *dev = container_of(work, struct bcm5974, mode_reset_work.work);
+
+ guard(mutex)(&dev->pm_mutex);
+ dev->last_mode_reset = jiffies;
+
+ error = bcm5974_wellspring_mode(dev, false);
+ if (error) {
+ dev_err(&dev->intf->dev, "reset to normal mode failed\n");
+ return;
+ }
+
+ fsleep(1000);
+
+ error = bcm5974_wellspring_mode(dev, true);
+ if (error)
+ dev_err(&dev->intf->dev, "mode switch after reset failed\n");
+}
+
static void bcm5974_irq_button(struct urb *urb)
{
struct bcm5974 *dev = urb->context;
@@ -752,10 +780,18 @@ static void bcm5974_irq_trackpad(struct urb *urb)
if (dev->tp_urb->actual_length == 2)
goto exit;
- if (report_tp_state(dev, dev->tp_urb->actual_length))
+ if (report_tp_state(dev, dev->tp_urb->actual_length)) {
dprintk(1, "bcm5974: bad trackpad package, length: %d\n",
dev->tp_urb->actual_length);
+ /* HID packet means we aren't in wellspring mode */
+ /* If we haven't tried a reset in the last second, try now */
+ if (dev->tp_urb->actual_length == 8 &&
+ time_after(jiffies, dev->last_mode_reset + msecs_to_jiffies(1000))) {
+ schedule_delayed_work(&dev->mode_reset_work, 0);
+ }
+ }
+
exit:
error = usb_submit_urb(dev->tp_urb, GFP_ATOMIC);
if (error)
@@ -906,6 +942,7 @@ static int bcm5974_probe(struct usb_interface *iface,
dev->intf = iface;
dev->input = input_dev;
dev->cfg = *cfg;
+ INIT_DELAYED_WORK(&dev->mode_reset_work, bcm5974_mode_reset_work);
mutex_init(&dev->pm_mutex);
/* setup urbs */
@@ -998,6 +1035,7 @@ static void bcm5974_disconnect(struct usb_interface *iface)
{
struct bcm5974 *dev = usb_get_intfdata(iface);
+ disable_delayed_work_sync(&dev->mode_reset_work);
usb_set_intfdata(iface, NULL);
input_unregister_device(dev->input);
---
base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
change-id: 20260207-bcm5974-reset-85ccdfca9641
Best regards,
--
Liam Mitchell <mitchell.liam@gmail.com>Hi Liam, On Fri, Feb 13, 2026 at 10:25:40AM +0100, Liam Mitchell wrote: > Mode switches sent before control response are ignored. > On receiving unknown 8-byte packets, assume that mode switch was ignored > and reset by switching to normal mode, waiting then switching back to > wellspring mode. > > --- > This patch addresses an issue where the bcm5974 driver switches modes > before the device is ready, resulting in an unresponsive trackpad and > "bcm5974: bad trackpad package, length: 8" repeated in logs. > > Discussion of issue in the thread: > https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/ > > This fix is conservative, avoiding changing existing mode-switch > behavior because I cannot test all variations of hardware. > > On receiving an unknown 8-byte packet, we assume the device is not in > wellspring mode and schedule an asynchronous mode reset. > > Signed-off-by: Liam Mitchell <mitchell.liam@gmail.com> > Link: https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/ > --- > Changes in v2: > - mutex_lock -> guard(mutex) > - dprintk -> dev_err > - msleep -> fsleep > - removed 0 init > - cancel_work_sync -> disable_delayed_work_sync > - work_struct -> delayed_work My apologies, I did not mean to request switch to delayed work, just to switch to disable_work_sync(). I fixed this up on my side and applied. Thanks. -- Dmitry
Hi Liam,
thanks for seeing this through! Looks good to me.
Acked-by: Henrik Rydberg <rydberg@bitmath.org>
On 2/13/26 10:25 AM, Liam Mitchell wrote:
> Mode switches sent before control response are ignored.
> On receiving unknown 8-byte packets, assume that mode switch was ignored
> and reset by switching to normal mode, waiting then switching back to
> wellspring mode.
>
> ---
> This patch addresses an issue where the bcm5974 driver switches modes
> before the device is ready, resulting in an unresponsive trackpad and
> "bcm5974: bad trackpad package, length: 8" repeated in logs.
>
> Discussion of issue in the thread:
> https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/
>
> This fix is conservative, avoiding changing existing mode-switch
> behavior because I cannot test all variations of hardware.
>
> On receiving an unknown 8-byte packet, we assume the device is not in
> wellspring mode and schedule an asynchronous mode reset.
>
> Signed-off-by: Liam Mitchell <mitchell.liam@gmail.com>
> Link: https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/
> ---
> Changes in v2:
> - mutex_lock -> guard(mutex)
> - dprintk -> dev_err
> - msleep -> fsleep
> - removed 0 init
> - cancel_work_sync -> disable_delayed_work_sync
> - work_struct -> delayed_work
> - Link to v1: https://lore.kernel.org/r/20260207-bcm5974-reset-v1-1-af7163903fa6@gmail.com
> ---
> drivers/input/mouse/bcm5974.c | 40 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
> index dfdfb59cc8b5..6ee766ed8402 100644
> --- a/drivers/input/mouse/bcm5974.c
> +++ b/drivers/input/mouse/bcm5974.c
> @@ -286,6 +286,8 @@ struct bcm5974 {
> const struct tp_finger *index[MAX_FINGERS]; /* finger index data */
> struct input_mt_pos pos[MAX_FINGERS]; /* position array */
> int slots[MAX_FINGERS]; /* slot assignments */
> + struct delayed_work mode_reset_work;
> + unsigned long last_mode_reset;
> };
>
> /* trackpad finger block data, le16-aligned */
> @@ -696,6 +698,32 @@ static int bcm5974_wellspring_mode(struct bcm5974 *dev, bool on)
> return retval;
> }
>
> +/*
> + * Mode switches sent before the control response are ignored.
> + * Fixing this state requires switching to normal mode and waiting
> + * about 1ms before switching back to wellspring mode.
> + */
> +static void bcm5974_mode_reset_work(struct work_struct *work)
> +{
> + int error;
> + struct bcm5974 *dev = container_of(work, struct bcm5974, mode_reset_work.work);
> +
> + guard(mutex)(&dev->pm_mutex);
> + dev->last_mode_reset = jiffies;
> +
> + error = bcm5974_wellspring_mode(dev, false);
> + if (error) {
> + dev_err(&dev->intf->dev, "reset to normal mode failed\n");
> + return;
> + }
> +
> + fsleep(1000);
> +
> + error = bcm5974_wellspring_mode(dev, true);
> + if (error)
> + dev_err(&dev->intf->dev, "mode switch after reset failed\n");
> +}
> +
> static void bcm5974_irq_button(struct urb *urb)
> {
> struct bcm5974 *dev = urb->context;
> @@ -752,10 +780,18 @@ static void bcm5974_irq_trackpad(struct urb *urb)
> if (dev->tp_urb->actual_length == 2)
> goto exit;
>
> - if (report_tp_state(dev, dev->tp_urb->actual_length))
> + if (report_tp_state(dev, dev->tp_urb->actual_length)) {
> dprintk(1, "bcm5974: bad trackpad package, length: %d\n",
> dev->tp_urb->actual_length);
>
> + /* HID packet means we aren't in wellspring mode */
> + /* If we haven't tried a reset in the last second, try now */
> + if (dev->tp_urb->actual_length == 8 &&
> + time_after(jiffies, dev->last_mode_reset + msecs_to_jiffies(1000))) {
> + schedule_delayed_work(&dev->mode_reset_work, 0);
> + }
> + }
> +
> exit:
> error = usb_submit_urb(dev->tp_urb, GFP_ATOMIC);
> if (error)
> @@ -906,6 +942,7 @@ static int bcm5974_probe(struct usb_interface *iface,
> dev->intf = iface;
> dev->input = input_dev;
> dev->cfg = *cfg;
> + INIT_DELAYED_WORK(&dev->mode_reset_work, bcm5974_mode_reset_work);
> mutex_init(&dev->pm_mutex);
>
> /* setup urbs */
> @@ -998,6 +1035,7 @@ static void bcm5974_disconnect(struct usb_interface *iface)
> {
> struct bcm5974 *dev = usb_get_intfdata(iface);
>
> + disable_delayed_work_sync(&dev->mode_reset_work);
> usb_set_intfdata(iface, NULL);
>
> input_unregister_device(dev->input);
>
> ---
> base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
> change-id: 20260207-bcm5974-reset-85ccdfca9641
>
> Best regards,
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