linux-kernel - Re: [PATCH] dell-rbtn: Ignore ACPI notifications if device is suspended

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Date:	Sat, 21 Nov 2015 20:18:04 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	Gabriele Mazzotta <gabriele.mzt@...il.com>
Cc:	dvhart@...radead.org, platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>, linux-acpi@...r.kernel.org
Subject: Re: [PATCH] dell-rbtn: Ignore ACPI notifications if device is suspended

On Saturday 21 November 2015 15:16:15 Gabriele Mazzotta wrote:
> Some BIOSes unconditionally send an ACPI notification to RBTN when
> the system is resuming from suspend. This makes dell-rbtn send an
> input event to userspace as if a function key was pressed. Prevent
> this by ignoring all the notifications received while the device is
> suspended.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=106031
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@...il.com>

Looks like we need to ignore ACPI events when RBTN device is suspended. 
So for me it is OK. If ACPI people are OK with implementation, add my 
Acked-By: Pali Rohár <pali.rohar@...il.com>

> ---
>  drivers/platform/x86/dell-rbtn.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/platform/x86/dell-rbtn.c
> b/drivers/platform/x86/dell-rbtn.c index cd410e3..1d64b72 100644
> --- a/drivers/platform/x86/dell-rbtn.c
> +++ b/drivers/platform/x86/dell-rbtn.c
> @@ -28,6 +28,7 @@ struct rbtn_data {
>  	enum rbtn_type type;
>  	struct rfkill *rfkill;
>  	struct input_dev *input_dev;
> +	bool suspended;
>  };
> 
> 
> @@ -220,9 +221,33 @@ static const struct acpi_device_id rbtn_ids[] =
> { { "", 0 },
>  };
> 
> +#ifdef CONFIG_PM_SLEEP
> +static int rbtn_suspend(struct device *dev)
> +{
> +	struct acpi_device *device = to_acpi_device(dev);
> +	struct rbtn_data *rbtn_data = acpi_driver_data(device);
> +
> +	rbtn_data->suspended = true;
> +
> +	return 0;
> +}
> +
> +static int rbtn_resume(struct device *dev)
> +{
> +	struct acpi_device *device = to_acpi_device(dev);
> +	struct rbtn_data *rbtn_data = acpi_driver_data(device);
> +
> +	rbtn_data->suspended = false;
> +
> +	return 0;
> +}
> +#endif
> +static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
> +
>  static struct acpi_driver rbtn_driver = {
>  	.name = "dell-rbtn",
>  	.ids = rbtn_ids,
> +	.drv.pm = &rbtn_pm_ops,
>  	.ops = {
>  		.add = rbtn_add,
>  		.remove = rbtn_remove,
> @@ -384,6 +409,9 @@ static void rbtn_notify(struct acpi_device
> *device, u32 event) {
>  	struct rbtn_data *rbtn_data = device->driver_data;
> 
> +	if (rbtn_data->suspended)
> +		return;
> +
>  	if (event != 0x80) {
>  		dev_info(&device->dev, "Received unknown event (0x%x)\n",
>  			 event);

CCing Rafael & linux-acpi.

Is this correct way (via "suspended" variable and hooks in PM) how to 
ignore ACPI events when device is suspended?

-- 
Pali Rohár
pali.rohar@...il.com

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