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Fri, 13 Feb 2026 01:25:55 -0800 (PST) Received: from [192.168.178.21] ([2001:9e8:fba1:9200:22c9:d0ff:fe7b:79cb]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48370a41be2sm24302765e9.1.2026.02.13.01.25.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Feb 2026 01:25:55 -0800 (PST) From: Liam Mitchell Date: Fri, 13 Feb 2026 10:25:40 +0100 Subject: [PATCH v2] bcm5974: recover from failed mode switch Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260213-bcm5974-reset-v2-1-1837851336b0@gmail.com> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/3XMQQ7CIBCF4as0sxYDtAXrynuYLpAO7SRSDDRE0 3B3sXuX/0vet0PCSJjg2uwQMVOisNaQpwbsYtYZGU21QXKpuOSaPazvB92xiAk3dumtnZw1g+o E1M8roqP34d3H2gulLcTPwWfxW/9JWTDBjNNCtQNvnVG32Rt6nm3wMJZSvnMijjyqAAAA X-Change-ID: 20260207-bcm5974-reset-85ccdfca9641 To: Henrik Rydberg , Dmitry Torokhov Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Liam Mitchell X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1770974754; l=4355; i=mitchell.liam@gmail.com; s=20260207; h=from:subject:message-id; bh=4Ij2NBoCIlNWCY0qDQILXOuDEmN9GJTc5JcYF6tAQvU=; b=5IeXF00uQBUO/z2qvJjGtiewVRhLOQcBzlCo/8zJFtPN6yIeeXjKEKqGpMl72WbDVURD3jslk r+4eNYOzKYyDkxPkBADotIJksVOcYTLxP39gCdNeDU2rMoHfwkWOJuE X-Developer-Key: i=mitchell.liam@gmail.com; a=ed25519; pk=Y9mPqBk1OuHZ0OaUZ5a8Nc5X7YHs7+SKiNwUfcLfPmg= 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. Acked-by: Henrik Rydberg --- 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=3D5q=3D= 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 Link: https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg= =3D5q=3DDr2Z1OQc6RXydSYA@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-af71639= 03fa6@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; }; =20 /* trackpad finger block data, le16-aligned */ @@ -696,6 +698,32 @@ static int bcm5974_wellspring_mode(struct bcm5974 *dev= , bool on) return retval; } =20 +/* + * 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 =3D container_of(work, struct bcm5974, mode_reset_wor= k.work); + + guard(mutex)(&dev->pm_mutex); + dev->last_mode_reset =3D jiffies; + + error =3D bcm5974_wellspring_mode(dev, false); + if (error) { + dev_err(&dev->intf->dev, "reset to normal mode failed\n"); + return; + } + + fsleep(1000); + + error =3D 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 =3D urb->context; @@ -752,10 +780,18 @@ static void bcm5974_irq_trackpad(struct urb *urb) if (dev->tp_urb->actual_length =3D=3D 2) goto exit; =20 - 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); =20 + /* 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 =3D=3D 8 && + time_after(jiffies, dev->last_mode_reset + msecs_to_jiffies(1000))) { + schedule_delayed_work(&dev->mode_reset_work, 0); + } + } + exit: error =3D usb_submit_urb(dev->tp_urb, GFP_ATOMIC); if (error) @@ -906,6 +942,7 @@ static int bcm5974_probe(struct usb_interface *iface, dev->intf =3D iface; dev->input =3D input_dev; dev->cfg =3D *cfg; + INIT_DELAYED_WORK(&dev->mode_reset_work, bcm5974_mode_reset_work); mutex_init(&dev->pm_mutex); =20 /* setup urbs */ @@ -998,6 +1035,7 @@ static void bcm5974_disconnect(struct usb_interface *i= face) { struct bcm5974 *dev =3D usb_get_intfdata(iface); =20 + disable_delayed_work_sync(&dev->mode_reset_work); usb_set_intfdata(iface, NULL); =20 input_unregister_device(dev->input); --- base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449 change-id: 20260207-bcm5974-reset-85ccdfca9641 Best regards, --=20 Liam Mitchell