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[PATCH] HID: rmi: Make sure the HID device is opened on resume

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  [PATCH] HID: rmi: Make sure the HID device is opened on resume Lyude <lyude@redhat.com> - 2017-07-23 03:20 +0200
    Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-23 12:00 +0200
      Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Lyude Paul <lyude@redhat.com> - 2017-07-24 19:50 +0200
        Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Jiri Kosina <jikos@kernel.org> - 2017-07-24 21:30 +0200
          Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Lyude Paul <lyude@redhat.com> - 2017-07-24 21:50 +0200
    Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Benjamin Tissoires <benjamin.tissoires@redhat.com> - 2017-07-24 10:20 +0200
      Re: [PATCH] HID: rmi: Make sure the HID device is opened on resume Lyude Paul <lyude@redhat.com> - 2017-07-24 20:00 +0200

#1694239 — [PATCH] HID: rmi: Make sure the HID device is opened on resume

So it looks like that suspend/resume has actually always been broken on
hid-rmi. The fact it worked was a rather silly coincidence that was
relying on the HID device to already be opened upon resume. This means
that so long as anything was reading the /dev/input/eventX node for for
an RMI device, it would suspend and resume correctly. As well, if
nothing happened to be keeping the HID device away it would shut off,
then the RMI driver would get confused on resume when it stopped
responding and explode.

So, call hid_hw_open() in rmi_post_resume() so we make sure that the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.

Signed-off-by: Lyude <lyude@redhat.com>
Cc: Andrew Duggan <aduggan@synaptics.com>
Cc: stable@vger.kernel.org
---
 drivers/hid/hid-rmi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 5b40c2614599..e7d124f9a27f 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c
@@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device *hdev)
 {
 	struct rmi_data *data = hid_get_drvdata(hdev);
 	struct rmi_device *rmi_dev = data->xport.rmi_dev;
-	int ret;
+	int ret = 0;
 
 	if (!(data->device_flags & RMI_DEVICE))
 		return 0;
 
-	ret = rmi_reset_attn_mode(hdev);
+	/* Make sure the HID device is ready to receive events */
+	ret = hid_hw_open(hdev);
 	if (ret)
 		return ret;
 
+	ret = rmi_reset_attn_mode(hdev);
+	if (ret)
+		goto out;
+
 	ret = rmi_driver_resume(rmi_dev, false);
 	if (ret) {
 		hid_warn(hdev, "Failed to resume device: %d\n", ret);
-		return ret;
+		goto out;
 	}
 
-	return 0;
+out:
+	hid_hw_close(hdev);
+	return ret;
 }
 #endif /* CONFIG_PM */
 
-- 
2.13.3

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#1694269

On Sun, Jul 23, 2017 at 4:15 AM, Lyude <lyude@redhat.com> wrote:

> So, call hid_hw_open() in rmi_post_resume() so we make sure that the
> device is alive before we try talking to it.
>
> This fixes RMI device suspend/resume over HID.

> -       int ret;
> +       int ret = 0;

What's the point?

>
>         if (!(data->device_flags & RMI_DEVICE))
>                 return 0;
>
> -       ret = rmi_reset_attn_mode(hdev);
> +       /* Make sure the HID device is ready to receive events */
> +       ret = hid_hw_open(hdev);
>         if (ret)
>                 return ret;

-- 
With Best Regards,
Andy Shevchenko

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#1694950

On Sun, 2017-07-23 at 12:54 +0300, Andy Shevchenko wrote:
> On Sun, Jul 23, 2017 at 4:15 AM, Lyude <lyude@redhat.com> wrote:
> 
> > So, call hid_hw_open() in rmi_post_resume() so we make sure that
> > the
> > device is alive before we try talking to it.
> > 
> > This fixes RMI device suspend/resume over HID.
> > -       int ret;
> > +       int ret = 0;
> 
> What's the point?
So that we can use the same out: label at the end of the function that
calls hid_hw_close() to return success. This being said though I just
realized that setting ret will initialize it to 0 anyway, so I guess
this can be dropped
> 
> > 
> >         if (!(data->device_flags & RMI_DEVICE))
> >                 return 0;
> > 
> > -       ret = rmi_reset_attn_mode(hdev);
> > +       /* Make sure the HID device is ready to receive events */
> > +       ret = hid_hw_open(hdev);
> >         if (ret)
> >                 return ret;
> 
> 

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#1695027

On Mon, 24 Jul 2017, Lyude Paul wrote:

> > > So, call hid_hw_open() in rmi_post_resume() so we make sure that
> > > the
> > > device is alive before we try talking to it.
> > > 
> > > This fixes RMI device suspend/resume over HID.
> > > -       int ret;
> > > +       int ret = 0;
> > 
> > What's the point?
> So that we can use the same out: label at the end of the function that
> calls hid_hw_close() to return success. This being said though I just
> realized that setting ret will initialize it to 0 anyway, so I guess
> this can be dropped

Andy's point was that hid_hw_open() is obviously re-initializing the ret 
before its first use as a return value, so there is no need to initialize 
it at a declaration time.

-- 
Jiri Kosina
SUSE Labs

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#1695040

Yeah I noticed that, sorry if my response wasn't very clear! Should
probably wait to have my morning coffee before responding to these
messages :P

On Mon, 2017-07-24 at 21:28 +0200, Jiri Kosina wrote:
> On Mon, 24 Jul 2017, Lyude Paul wrote:
> 
> > > > So, call hid_hw_open() in rmi_post_resume() so we make sure
> > > > that
> > > > the
> > > > device is alive before we try talking to it.
> > > > 
> > > > This fixes RMI device suspend/resume over HID.
> > > > -       int ret;
> > > > +       int ret = 0;
> > > 
> > > What's the point?
> > 
> > So that we can use the same out: label at the end of the function
> > that
> > calls hid_hw_close() to return success. This being said though I
> > just
> > realized that setting ret will initialize it to 0 anyway, so I
> > guess
> > this can be dropped
> 
> Andy's point was that hid_hw_open() is obviously re-initializing the
> ret 
> before its first use as a return value, so there is no need to
> initialize 
> it at a declaration time.
> 

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#1694531

On Jul 22 2017 or thereabouts, Lyude wrote:
> So it looks like that suspend/resume has actually always been broken on
> hid-rmi. The fact it worked was a rather silly coincidence that was
> relying on the HID device to already be opened upon resume. This means
> that so long as anything was reading the /dev/input/eventX node for for
> an RMI device, it would suspend and resume correctly. As well, if
> nothing happened to be keeping the HID device away it would shut off,
> then the RMI driver would get confused on resume when it stopped
> responding and explode.

Oh, good finding. However, given that there are few other drivers not
calling hid_hw_open during their .reset_resume() callback and those
drivers also are communicating with the device, I wonder if we should
not have something more generic, that will call hid_hw_open/close in the
transport layer directly.

I do not recall having seen bugs for Wacom devices, so maybe this is
something i2c-hid related, but it wouldn't hurt I guess to open/close
the device before calling reset_resume.

Cheers,
Benjamin

> 
> So, call hid_hw_open() in rmi_post_resume() so we make sure that the
> device is alive before we try talking to it.
> 
> This fixes RMI device suspend/resume over HID.
> 
> Signed-off-by: Lyude <lyude@redhat.com>
> Cc: Andrew Duggan <aduggan@synaptics.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/hid/hid-rmi.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
> index 5b40c2614599..e7d124f9a27f 100644
> --- a/drivers/hid/hid-rmi.c
> +++ b/drivers/hid/hid-rmi.c
> @@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device *hdev)
>  {
>  	struct rmi_data *data = hid_get_drvdata(hdev);
>  	struct rmi_device *rmi_dev = data->xport.rmi_dev;
> -	int ret;
> +	int ret = 0;
>  
>  	if (!(data->device_flags & RMI_DEVICE))
>  		return 0;
>  
> -	ret = rmi_reset_attn_mode(hdev);
> +	/* Make sure the HID device is ready to receive events */
> +	ret = hid_hw_open(hdev);
>  	if (ret)
>  		return ret;
>  
> +	ret = rmi_reset_attn_mode(hdev);
> +	if (ret)
> +		goto out;
> +
>  	ret = rmi_driver_resume(rmi_dev, false);
>  	if (ret) {
>  		hid_warn(hdev, "Failed to resume device: %d\n", ret);
> -		return ret;
> +		goto out;
>  	}
>  
> -	return 0;
> +out:
> +	hid_hw_close(hdev);
> +	return ret;
>  }
>  #endif /* CONFIG_PM */
>  
> -- 
> 2.13.3
> 

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#1694966

On Mon, 2017-07-24 at 10:15 +0200, Benjamin Tissoires wrote:
> On Jul 22 2017 or thereabouts, Lyude wrote:
> > So it looks like that suspend/resume has actually always been
> > broken on
> > hid-rmi. The fact it worked was a rather silly coincidence that was
> > relying on the HID device to already be opened upon resume. This
> > means
> > that so long as anything was reading the /dev/input/eventX node for
> > for
> > an RMI device, it would suspend and resume correctly. As well, if
> > nothing happened to be keeping the HID device away it would shut
> > off,
> > then the RMI driver would get confused on resume when it stopped
> > responding and explode.
> 
> Oh, good finding. However, given that there are few other drivers not
> calling hid_hw_open during their .reset_resume() callback and those
> drivers also are communicating with the device, I wonder if we should
> not have something more generic, that will call hid_hw_open/close in
> the
> transport layer directly.
This sounds like a good idea, especially since a call like this is
rather easy to miss. I will look into doing that for v2
> 
> I do not recall having seen bugs for Wacom devices, so maybe this is
> something i2c-hid related, but it wouldn't hurt I guess to open/close
> the device before calling reset_resume.
> 
> Cheers,
> Benjamin
> 
> > 
> > So, call hid_hw_open() in rmi_post_resume() so we make sure that
> > the
> > device is alive before we try talking to it.
> > 
> > This fixes RMI device suspend/resume over HID.
> > 
> > Signed-off-by: Lyude <lyude@redhat.com>
> > Cc: Andrew Duggan <aduggan@synaptics.com>
> > Cc: stable@vger.kernel.org
> > ---
> >  drivers/hid/hid-rmi.c | 15 +++++++++++----
> >  1 file changed, 11 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
> > index 5b40c2614599..e7d124f9a27f 100644
> > --- a/drivers/hid/hid-rmi.c
> > +++ b/drivers/hid/hid-rmi.c
> > @@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device
> > *hdev)
> >  {
> >  	struct rmi_data *data = hid_get_drvdata(hdev);
> >  	struct rmi_device *rmi_dev = data->xport.rmi_dev;
> > -	int ret;
> > +	int ret = 0;
> >  
> >  	if (!(data->device_flags & RMI_DEVICE))
> >  		return 0;
> >  
> > -	ret = rmi_reset_attn_mode(hdev);
> > +	/* Make sure the HID device is ready to receive events */
> > +	ret = hid_hw_open(hdev);
> >  	if (ret)
> >  		return ret;
> >  
> > +	ret = rmi_reset_attn_mode(hdev);
> > +	if (ret)
> > +		goto out;
> > +
> >  	ret = rmi_driver_resume(rmi_dev, false);
> >  	if (ret) {
> >  		hid_warn(hdev, "Failed to resume device: %d\n",
> > ret);
> > -		return ret;
> > +		goto out;
> >  	}
> >  
> > -	return 0;
> > +out:
> > +	hid_hw_close(hdev);
> > +	return ret;
> >  }
> >  #endif /* CONFIG_PM */
> >  
> > -- 
> > 2.13.3
> > 

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