[PATCH] usbhid: add error handling

This patch (as628c) adds error handling to the USB HID core.  When an
error is reported for an interrupt URB, the driver will do delayed
retries, at increasing intervals, for up to one second.  If that doesn't
work, it will try to reset the device.  Testing by users has shown that
both the retries and the resets end up getting used.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/input/hid-core.c

@@ -902,6 +902,99 @@ static int hid_input_report(int type, struct urb *urb, int interrupt, struct pt_
 	return 0;
 }
 
+/*
+ * Input submission and I/O error handler.
+ */
+
+static void hid_io_error(struct hid_device *hid);
+
+/* Start up the input URB */
+static int hid_start_in(struct hid_device *hid)
+{
+	unsigned long flags;
+	int rc = 0;
+
+	spin_lock_irqsave(&hid->inlock, flags);
+	if (hid->open > 0 && !test_bit(HID_SUSPENDED, &hid->iofl) &&
+			!test_and_set_bit(HID_IN_RUNNING, &hid->iofl)) {
+		rc = usb_submit_urb(hid->urbin, GFP_ATOMIC);
+		if (rc != 0)
+			clear_bit(HID_IN_RUNNING, &hid->iofl);
+	}
+	spin_unlock_irqrestore(&hid->inlock, flags);
+	return rc;
+}
+
+/* I/O retry timer routine */
+static void hid_retry_timeout(unsigned long _hid)
+{
+	struct hid_device *hid = (struct hid_device *) _hid;
+
+	dev_dbg(&hid->intf->dev, "retrying intr urb\n");
+	if (hid_start_in(hid))
+		hid_io_error(hid);
+}
+
+/* Workqueue routine to reset the device */
+static void hid_reset(void *_hid)
+{
+	struct hid_device *hid = (struct hid_device *) _hid;
+	int rc_lock, rc;
+
+	dev_dbg(&hid->intf->dev, "resetting device\n");
+	rc = rc_lock = usb_lock_device_for_reset(hid->dev, hid->intf);
+	if (rc_lock >= 0) {
+		rc = usb_reset_device(hid->dev);
+		if (rc_lock)
+			usb_unlock_device(hid->dev);
+	}
+	clear_bit(HID_RESET_PENDING, &hid->iofl);
+
+	if (rc == 0) {
+		hid->retry_delay = 0;
+		if (hid_start_in(hid))
+			hid_io_error(hid);
+	} else if (!(rc == -ENODEV || rc == -EHOSTUNREACH || rc == -EINTR))
+		err("can't reset device, %s-%s/input%d, status %d",
+				hid->dev->bus->bus_name,
+				hid->dev->devpath,
+				hid->ifnum, rc);
+}
+
+/* Main I/O error handler */
+static void hid_io_error(struct hid_device *hid)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&hid->inlock, flags);
+
+	/* Stop when disconnected */
+	if (usb_get_intfdata(hid->intf) == NULL)
+		goto done;
+
+	/* When an error occurs, retry at increasing intervals */
+	if (hid->retry_delay == 0) {
+		hid->retry_delay = 13;	/* Then 26, 52, 104, 104, ... */
+		hid->stop_retry = jiffies + msecs_to_jiffies(1000);
+	} else if (hid->retry_delay < 100)
+		hid->retry_delay *= 2;
+
+	if (time_after(jiffies, hid->stop_retry)) {
+
+		/* Retries failed, so do a port reset */
+		if (!test_and_set_bit(HID_RESET_PENDING, &hid->iofl)) {
+			if (schedule_work(&hid->reset_work))
+				goto done;
+			clear_bit(HID_RESET_PENDING, &hid->iofl);
+		}
+	}
+
+	mod_timer(&hid->io_retry,
+			jiffies + msecs_to_jiffies(hid->retry_delay));
+done:
+	spin_unlock_irqrestore(&hid->inlock, flags);
+}
+
 /*
  * Input interrupt completion handler.
  */
@@ -913,25 +1006,35 @@ static void hid_irq_in(struct urb *urb, struct pt_regs *regs)
 
 	switch (urb->status) {
 		case 0:			/* success */
+			hid->retry_delay = 0;
 			hid_input_report(HID_INPUT_REPORT, urb, 1, regs);
 			break;
 		case -ECONNRESET:	/* unlink */
 		case -ENOENT:
-		case -EPERM:
 		case -ESHUTDOWN:	/* unplug */
-		case -EILSEQ:		/* unplug timeout on uhci */
+			clear_bit(HID_IN_RUNNING, &hid->iofl);
 			return;
+		case -EILSEQ:		/* protocol error or unplug */
+		case -EPROTO:		/* protocol error or unplug */
 		case -ETIMEDOUT:	/* NAK */
-			break;
+			clear_bit(HID_IN_RUNNING, &hid->iofl);
+			hid_io_error(hid);
+			return;
 		default:		/* error */
 			warn("input irq status %d received", urb->status);
 	}
 
 	status = usb_submit_urb(urb, SLAB_ATOMIC);
-	if (status)
-		err("can't resubmit intr, %s-%s/input%d, status %d",
-				hid->dev->bus->bus_name, hid->dev->devpath,
-				hid->ifnum, status);
+	if (status) {
+		clear_bit(HID_IN_RUNNING, &hid->iofl);
+		if (status != -EPERM) {
+			err("can't resubmit intr, %s-%s/input%d, status %d",
+					hid->dev->bus->bus_name,
+					hid->dev->devpath,
+					hid->ifnum, status);
+			hid_io_error(hid);
+		}
+	}
 }
 
 /*
@@ -1093,8 +1196,9 @@ static void hid_irq_out(struct urb *urb, struct pt_regs *regs)
 		case 0:			/* success */
 			break;
 		case -ESHUTDOWN:	/* unplug */
-		case -EILSEQ:		/* unplug timeout on uhci */
 			unplug = 1;
+		case -EILSEQ:		/* protocol error or unplug */
+		case -EPROTO:		/* protocol error or unplug */
 		case -ECONNRESET:	/* unlink */
 		case -ENOENT:
 			break;
@@ -1141,8 +1245,9 @@ static void hid_ctrl(struct urb *urb, struct pt_regs *regs)
 				hid_input_report(hid->ctrl[hid->ctrltail].report->type, urb, 0, regs);
 			break;
 		case -ESHUTDOWN:	/* unplug */
-		case -EILSEQ:		/* unplug timectrl on uhci */
 			unplug = 1;
+		case -EILSEQ:		/* protocol error or unplug */
+		case -EPROTO:		/* protocol error or unplug */
 		case -ECONNRESET:	/* unlink */
 		case -ENOENT:
 		case -EPIPE:		/* report not available */
@@ -1255,14 +1360,9 @@ static int hid_get_class_descriptor(struct usb_device *dev, int ifnum,
 
 int hid_open(struct hid_device *hid)
 {
-	if (hid->open++)
-		return 0;
-
-	hid->urbin->dev = hid->dev;
-
-	if (usb_submit_urb(hid->urbin, GFP_KERNEL))
-		return -EIO;
-
+	++hid->open;
+	if (hid_start_in(hid))
+		hid_io_error(hid);
 	return 0;
 }
 
@@ -1787,6 +1887,10 @@ static struct hid_device *usb_hid_configure(struct usb_interface *intf)
 
 	init_waitqueue_head(&hid->wait);
 
+	INIT_WORK(&hid->reset_work, hid_reset, hid);
+	setup_timer(&hid->io_retry, hid_retry_timeout, (unsigned long) hid);
+
+	spin_lock_init(&hid->inlock);
 	spin_lock_init(&hid->outlock);
 	spin_lock_init(&hid->ctrllock);
 
@@ -1855,11 +1959,16 @@ static void hid_disconnect(struct usb_interface *intf)
 	if (!hid)
 		return;
 
+	spin_lock_irq(&hid->inlock);	/* Sync with error handler */
 	usb_set_intfdata(intf, NULL);
+	spin_unlock_irq(&hid->inlock);
 	usb_kill_urb(hid->urbin);
 	usb_kill_urb(hid->urbout);
 	usb_kill_urb(hid->urbctrl);
 
+	del_timer_sync(&hid->io_retry);
+	flush_scheduled_work();
+
 	if (hid->claimed & HID_CLAIMED_INPUT)
 		hidinput_disconnect(hid);
 	if (hid->claimed & HID_CLAIMED_HIDDEV)
@@ -1934,6 +2043,10 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct hid_device *hid = usb_get_intfdata (intf);
 
+	spin_lock_irq(&hid->inlock);	/* Sync with error handler */
+	set_bit(HID_SUSPENDED, &hid->iofl);
+	spin_unlock_irq(&hid->inlock);
+	del_timer(&hid->io_retry);
 	usb_kill_urb(hid->urbin);
 	dev_dbg(&intf->dev, "suspend\n");
 	return 0;
@@ -1944,10 +2057,8 @@ static int hid_resume(struct usb_interface *intf)
 	struct hid_device *hid = usb_get_intfdata (intf);
 	int status;
 
-	if (hid->open)
-		status = usb_submit_urb(hid->urbin, GFP_NOIO);
-	else
-		status = 0;
+	clear_bit(HID_SUSPENDED, &hid->iofl);
+	status = hid_start_in(hid);
 	dev_dbg(&intf->dev, "resume status %d\n", status);
 	return status;
 }

drivers/usb/input/hid.h

@@ -31,6 +31,8 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/list.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
 
 /*
  * USB HID (Human Interface Device) interface class code
@@ -370,6 +372,9 @@ struct hid_control_fifo {
 
 #define HID_CTRL_RUNNING	1
 #define HID_OUT_RUNNING		2
+#define HID_IN_RUNNING		3
+#define HID_RESET_PENDING	4
+#define HID_SUSPENDED		5
 
 struct hid_input {
 	struct list_head list;
@@ -393,12 +398,17 @@ struct hid_device {							/* device report descriptor */
 	int ifnum;							/* USB interface number */
 
 	unsigned long iofl;						/* I/O flags (CTRL_RUNNING, OUT_RUNNING) */
+	struct timer_list io_retry;					/* Retry timer */
+	unsigned long stop_retry;					/* Time to give up, in jiffies */
+	unsigned int retry_delay;					/* Delay length in ms */
+	struct work_struct reset_work;					/* Task context for resets */
 
 	unsigned int bufsize;						/* URB buffer size */
 
 	struct urb *urbin;						/* Input URB */
 	char *inbuf;							/* Input buffer */
 	dma_addr_t inbuf_dma;						/* Input buffer dma */
+	spinlock_t inlock;						/* Input fifo spinlock */
 
 	struct urb *urbctrl;						/* Control URB */
 	struct usb_ctrlrequest *cr;					/* Control request struct */