[PATCH 2/2] input: synaptics_usb: do not rely on input_dev->users

[Marcus Folkesson]

If the device is unused and suspended, a call to open will cause the
device to autoresume through the call to usb_autopm_get_interface().

input_dev->users is already incremented by the input subsystem,
therefore this expression will always be evaluated to true:

        if ((input_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
            usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
                retval = -EIO;
        }

The same URB will then be fail when resubmitted in synusb_open().

Introduce synusb->is_open to keep track of the state instead.

Signed-off-by: Marcus Folkesson <marcus.folkes...@gmail.com>
---
 drivers/input/mouse/synaptics_usb.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/input/mouse/synaptics_usb.c 
b/drivers/input/mouse/synaptics_usb.c
index 2c66913cf5a2..e2b726751220 100644
--- a/drivers/input/mouse/synaptics_usb.c
+++ b/drivers/input/mouse/synaptics_usb.c
@@ -84,6 +84,7 @@ struct synusb {
 
        /* serialize access to open/suspend */
        struct mutex pm_mutex;
+       bool is_open;
 
        /* input device related data structures */
        struct input_dev *input;
@@ -266,6 +267,7 @@ static int synusb_open(struct input_dev *dev)
        }
 
        synusb->intf->needs_remote_wakeup = 1;
+       synusb->is_open = 1;
 
 out:
        mutex_unlock(&synusb->pm_mutex);
@@ -283,6 +285,7 @@ static void synusb_close(struct input_dev *dev)
        mutex_lock(&synusb->pm_mutex);
        usb_kill_urb(synusb->urb);
        synusb->intf->needs_remote_wakeup = 0;
+       synusb->is_open = 0;
        mutex_unlock(&synusb->pm_mutex);
 
        if (!autopm_error)
@@ -485,12 +488,11 @@ static int synusb_suspend(struct usb_interface *intf, 
pm_message_t message)
 static int synusb_resume(struct usb_interface *intf)
 {
        struct synusb *synusb = usb_get_intfdata(intf);
-       struct input_dev *input_dev = synusb->input;
        int retval = 0;
 
        mutex_lock(&synusb->pm_mutex);
 
-       if ((input_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
+       if ((synusb->is_open || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
            usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
                retval = -EIO;
        }
@@ -513,10 +515,9 @@ static int synusb_pre_reset(struct usb_interface *intf)
 static int synusb_post_reset(struct usb_interface *intf)
 {
        struct synusb *synusb = usb_get_intfdata(intf);
-       struct input_dev *input_dev = synusb->input;
        int retval = 0;
 
-       if ((input_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
+       if ((synusb->is_open || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
            usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
                retval = -EIO;
        }
-- 
2.15.1