[RESEND PATCH 6/6] input: usbtouchscreen: do not rely on input_dev->users

Marcus Folkesson
2018-02-28T13:38:33Z

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->users || usbtouch->type->irq_always)
result = usb_submit_urb(usbtouch->irq, GFP_NOIO);

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

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

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

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index e964658203d8..0356ad792e40 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -114,6 +114,7 @@ struct usbtouch_usb {
struct input_dev *input;
struct usbtouch_device_info *type;
struct mutex pm_mutex; /* serialize access to open/suspend */
+ bool is_open;
char name[128];
char phys[64];
void *priv;
@@ -1466,6 +1467,7 @@ static int usbtouch_open(struct input_dev *input)
}

usbtouch->interface->needs_remote_wakeup = 1;
+ usbtouch->is_open = 1;
out_put:
mutex_unlock(&usbtouch->pm_mutex);
usb_autopm_put_interface(usbtouch->interface);
@@ -1481,6 +1483,7 @@ static void usbtouch_close(struct input_dev *input)
mutex_lock(&usbtouch->pm_mutex);
if (!usbtouch->type->irq_always)
usb_kill_urb(usbtouch->irq);
+ usbtouch->is_open = 0;
mutex_lock(&usbtouch->pm_mutex);

r = usb_autopm_get_interface(usbtouch->interface);
@@ -1502,11 +1505,10 @@ static int usbtouch_suspend
static int usbtouch_resume(struct usb_interface *intf)
{
struct usbtouch_usb *usbtouch = usb_get_intfdata(intf);
- struct input_dev *input = usbtouch->input;
int result = 0;

mutex_lock(&usbtouch->pm_mutex);
- if (input->users || usbtouch->type->irq_always)
+ if (usbtouch->is_open || usbtouch->type->irq_always)
result = usb_submit_urb(usbtouch->irq, GFP_NOIO);
mutex_unlock(&usbtouch->pm_mutex);

@@ -1516,7 +1518,6 @@ static int usbtouch_resume(struct usb_interface *intf)
static int usbtouch_reset_resume(struct usb_interface *intf)
{
struct usbtouch_usb *usbtouch = usb_get_intfdata(intf);
- struct input_dev *input = usbtouch->input;
int err = 0;

/* reinit the device */
@@ -1532,7 +1533,7 @@ static int usbtouch_reset_resume(struct usb_interface *intf)

/* restart IO if needed */
mutex_lock(&usbtouch->pm_mutex);
- if (input->users)
+ if (usbtouch->is_open)
err = usb_submit_urb(usbtouch->irq, GFP_NOIO);
mutex_unlock(&usbtouch->pm_mutex);

--
2.16.2