[RESEND PATCH 4/6] input: pegasus_notetaker: do not rely on input_dev->users

Marcus Folkesson
2018-02-28T13:39:00Z

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 (pegasus->dev->users && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
retval = -EIO;

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

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

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---
drivers/input/tablet/pegasus_notetaker.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
index 9ab1ed5e20e7..74c93e09c337 100644
--- a/drivers/input/tablet/pegasus_notetaker.c
+++ b/drivers/input/tablet/pegasus_notetaker.c
@@ -80,6 +80,7 @@ struct pegasus {

/* serialize access to open/suspend */
struct mutex pm_mutex;
+ bool is_open;

char name[128];
char phys[64];
@@ -232,6 +233,7 @@ static int pegasus_open(struct input_dev *dev)
if (error)
goto err_kill_urb;

+ pegasus->is_open = 1;
mutex_unlock(&pegasus->pm_mutex);
return 0;

@@ -251,6 +253,7 @@ static void pegasus_close(struct input_dev *dev)
mutex_lock(&pegasus->pm_mutex);
usb_kill_urb(pegasus->irq);
cancel_work_sync(&pegasus->init);
+ pegasus->is_open = 0;
mutex_unlock(&pegasus->pm_mutex);

usb_autopm_put_interface(pegasus->intf);
@@ -415,7 +418,7 @@ static int pegasus_resume(struct usb_interface *intf)
int retval = 0;

mutex_lock(&pegasus->pm_mutex);
- if (pegasus->dev->users && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
+ if (pegasus->is_open && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
retval = -EIO;
mutex_unlock(&pegasus->pm_mutex);

@@ -428,7 +431,7 @@ static int pegasus_reset_resume(struct usb_interface *intf)
int retval = 0;

mutex_lock(&pegasus->pm_mutex);
- if (pegasus->dev->users) {
+ if (pegasus->is_open) {
retval = pegasus_set_mode(pegasus, PEN_MODE_XY,
NOTETAKER_LED_MOUSE);
if (!retval && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
--
2.16.2