linux-kernel - Re: [PATCH v2] dell-rbtn: Ignore ACPI notifications if device is suspended

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Date:	Fri, 18 Mar 2016 18:57:33 +0300
From:	Andrei Borzenkov <arvidjaar@...il.com>
To:	Pali Rohár <pali.rohar@...il.com>,
	Gabriele Mazzotta <gabriele.mzt@...il.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	"D. Jared Dominguez" <Jared_Dominguez@...l.com>,
	"platform-driver-x86@...r.kernel.org" 
	<platform-driver-x86@...r.kernel.org>,
	Alex Hung <alex.hung@...onical.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] dell-rbtn: Ignore ACPI notifications if device is
 suspended

14.03.2016 14:45, Pali Rohár пишет:
> On Monday 14 March 2016 12:34:31 Gabriele Mazzotta wrote:
>> 2016-03-12 0:49 GMT+01:00 Gabriele Mazzotta <gabriele.mzt@...il.com>:
>>> 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>
>>> ---
>>>  drivers/platform/x86/dell-rbtn.c | 41 ++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 41 insertions(+)
>>>
>>> diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c
>>> index cd410e3..56b0da7 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 +221,44 @@ static const struct acpi_device_id rbtn_ids[] = {
>>>         { "", 0 },
>>>  };
>>>
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static void ACPI_SYSTEM_XFACE rbtn_acpi_clear_flag(void *context)
>>> +{
>>> +       struct rbtn_data *rbtn_data = context;
>>> +
>>> +       rbtn_data->suspended = false;
>>> +}
>>> +
>>> +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);
>>> +       acpi_status status;
>>> +
>>> +       status = acpi_os_execute(OSL_NOTIFY_HANDLER,
>>> +                        rbtn_acpi_clear_flag, rbtn_data);
>>> +       if (ACPI_FAILURE(status))
>>> +               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 +420,11 @@ static void rbtn_notify(struct acpi_device *device, u32 event)
>>>  {
>>>         struct rbtn_data *rbtn_data = device->driver_data;
>>>
>>> +       if (rbtn_data->suspended) {
>>> +               dev_dbg(&device->dev, "ACPI notification ignored\n");
>>> +               return;
>>> +       }
>>> +
>>>         if (event != 0x80) {
>>>                 dev_info(&device->dev, "Received unknown event (0x%x)\n",
>>>                          event);
>>> --
>>> 2.7.0
>>>
>>
>> I'm sorry, Pali, I must have missed your email address while sending
>> this updated version.
> 
> For me patch looks OK. I would suggest to add some comment about BIOS
> into code too.
> 
> Rafael, can you review that ACPI suspended/OSL_NOTIFY_HANDLER part?
> 
> Andrei, can you test if it now really fix it on your machine?
> 

TBH I'm still unsure if this fixes root cause or just decreases race
window, but so far after multiple suspend/resume cycles on my Dell
Latitude E5450 WiFi was restored every time. So

Tested-By: Andrei Borzenkov <arvidjaar@...il.com>