1 files changed, 27 insertions, 4 deletions

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index ebd68ed..8fc0f08 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -46,7 +46,7 @@
 #define MOD_AUTHOR	"Jarod Wilson <jarod@wilsonet.com>"
 #define MOD_DESC	"Driver for SoundGraph iMON MultiMedia IR/Display"
 #define MOD_NAME	"imon"
-#define MOD_VERSION	"0.9.2"
+#define MOD_VERSION	"0.9.3"
 
 #define DISPLAY_MINOR_BASE	144
 #define DEVICE_NAME	"lcd%d"
@@ -460,8 +460,9 @@ static int display_close(struct inode *inode, struct file *file)
 }
 
 /**
- * Sends a packet to the device -- this function must be called
- * with ictx->lock held.
+ * Sends a packet to the device -- this function must be called with
+ * ictx->lock held, or its unlock/lock sequence while waiting for tx
+ * to complete can/will lead to a deadlock.
  */
 static int send_packet(struct imon_context *ictx)
 {
@@ -991,12 +992,21 @@ static void imon_touch_display_timeout(unsigned long data)
  * the iMON remotes, and those used by the Windows MCE remotes (which is
  * really just RC-6), but only one or the other at a time, as the signals
  * are decoded onboard the receiver.
+ *
+ * This function gets called two different ways, one way is from
+ * rc_register_device, for initial protocol selection/setup, and the other is
+ * via a userspace-initiated protocol change request, either by direct sysfs
+ * prodding or by something like ir-keytable. In the rc_register_device case,
+ * the imon context lock is already held, but when initiated from userspace,
+ * it is not, so we must acquire it prior to calling send_packet, which
+ * requires that the lock is held.
  */
 static int imon_ir_change_protocol(struct rc_dev *rc, u64 rc_type)
 {
 	int retval;
 	struct imon_context *ictx = rc->priv;
 	struct device *dev = ictx->dev;
+	bool unlock = false;
 	unsigned char ir_proto_packet[] = {
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x86 };
 
@@ -1029,6 +1039,11 @@ static int imon_ir_change_protocol(struct rc_dev *rc, u64 rc_type)
 
 	memcpy(ictx->usb_tx_buf, &ir_proto_packet, sizeof(ir_proto_packet));
 
+	if (!mutex_is_locked(&ictx->lock)) {
+		unlock = true;
+		mutex_lock(&ictx->lock);
+	}
+
 	retval = send_packet(ictx);
 	if (retval)
 		goto out;
@@ -1037,6 +1052,9 @@ static int imon_ir_change_protocol(struct rc_dev *rc, u64 rc_type)
 	ictx->pad_mouse = false;
 
 out:
+	if (unlock)
+		mutex_unlock(&ictx->lock);
+
 	return retval;
 }
 
@@ -2134,6 +2152,7 @@ static struct imon_context *imon_init_intf0(struct usb_interface *intf)
 		goto rdev_setup_failed;
 	}
 
+	mutex_unlock(&ictx->lock);
 	return ictx;
 
 rdev_setup_failed:
@@ -2205,6 +2224,7 @@ static struct imon_context *imon_init_intf1(struct usb_interface *intf,
 		goto urb_submit_failed;
 	}
 
+	mutex_unlock(&ictx->lock);
 	return ictx;
 
 urb_submit_failed:
@@ -2299,6 +2319,8 @@ static int __devinit imon_probe(struct usb_interface *interface,
 	usb_set_intfdata(interface, ictx);
 
 	if (ifnum == 0) {
+		mutex_lock(&ictx->lock);
+
 		if (product == 0xffdc && ictx->rf_device) {
 			sysfs_err = sysfs_create_group(&interface->dev.kobj,
 						       &imon_rf_attr_group);
@@ -2309,13 +2331,14 @@ static int __devinit imon_probe(struct usb_interface *interface,
 
 		if (ictx->display_supported)
 			imon_init_display(ictx, interface);
+
+		mutex_unlock(&ictx->lock);
 	}
 
 	dev_info(dev, "iMON device (%04x:%04x, intf%d) on "
 		 "usb<%d:%d> initialized\n", vendor, product, ifnum,
 		 usbdev->bus->busnum, usbdev->devnum);
 
-	mutex_unlock(&ictx->lock);
 	mutex_unlock(&driver_lock);
 
 	return 0;