[RFC/RFT] Reset bcm5974 into wellspring mode when it forgets

[David Woodhouse <dwmw2@infradead.org>]

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Occasionally the trackpad in my MacBookPro 8,3 stops working, spewing
 'bcm5974: bad trackpad package, length: 8'

I haven't been able to reproduce this on demand, but it's annoying when
it does happen. I'm *assuming* that it's somehow forgotten what mode
it's supposed to be in. The fix for this on suspend/resume was to switch
it back to Wellspring mode again, so let's try that...

Untested, because my trackpad seems to *know* when I'm actually running
a kernel with this patch, and doesn't ever misbehave. I've played with
removing the *normal* mode switch in bcm5974_start_traffic() but can't
get it to produce the 'bad trackpad package' message at all in that
case, so the rest function doesn't get invoked.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
index 2baff1b..db0b3ab 100644
--- a/drivers/input/mouse/bcm5974.c
+++ b/drivers/input/mouse/bcm5974.c
@@ -244,6 +244,7 @@ struct bcm5974 {
 	struct bt_data *bt_data;	/* button transferred data */
 	struct urb *tp_urb;		/* trackpad usb request block */
 	u8 *tp_data;			/* trackpad transferred data */
+	struct work_struct reset_work;	/* reset to wellspring mode */
 	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 */
@@ -676,9 +677,14 @@ 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);
+		if (dev->tp_urb->actual_length == 8) {
+			/* Hm. Make sure it's in wellspring mode... */
+			schedule_work(&dev->reset_work);
+		}
+	}
 
 exit:
 	error = usb_submit_urb(dev->tp_urb, GFP_ATOMIC);
@@ -815,6 +821,14 @@ static int bcm5974_resume(struct usb_interface *iface)
 	return error;
 }
 
+static void bcm5974_mode_workfn(struct work_struct *work)
+{
+	struct bcm5974 *dev = container_of(work, struct bcm5974, reset_work);
+
+	dev_info(&dev->intf->dev, "Reset into wellspring mode...\n");
+	bcm5974_wellspring_mode(dev, true);
+}
+
 static int bcm5974_probe(struct usb_interface *iface,
 			 const struct usb_device_id *id)
 {
@@ -840,6 +854,7 @@ static int bcm5974_probe(struct usb_interface *iface,
 	dev->input = input_dev;
 	dev->cfg = *cfg;
 	mutex_init(&dev->pm_mutex);
+	INIT_WORK(&dev->reset_work, bcm5974_mode_workfn);
 
 	/* setup urbs */
 	if (cfg->tp_type == TYPE1) {
@@ -936,6 +951,7 @@ static void bcm5974_disconnect(struct usb_interface *iface)
 				  dev->bt_data, dev->bt_urb->transfer_dma);
 	usb_free_urb(dev->tp_urb);
 	usb_free_urb(dev->bt_urb);
+	cancel_work_sync(&dev->reset_work);
 	kfree(dev);
 }
 



-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation

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