linux-kernel - Re: [RESEND PATCH 2/6] input: synaptics_usb: do not rely on input

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Date:   Sat, 17 Mar 2018 11:10:51 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Marcus Folkesson <marcus.folkesson@...il.com>
Cc:     Arvind Yadav <arvind.yadav.cs@...il.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH 2/6] input: synaptics_usb: do not rely on
 input_dev->users

On Wed, Feb 28, 2018 at 02:37:59PM +0100, Marcus Folkesson wrote:
> 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.folkesson@...il.com>

Applied, thank you.

> ---
>  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;
>  	}
> -- 
> 2.16.2
> 

-- 
Dmitry