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

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Date:	Mon, 18 Apr 2016 14:31:26 +0200
From:	Pali Rohár <pali.rohar@...il.com>
To:	Andrei Borzenkov <arvidjaar@...il.com>
Cc:	Gabriele Mazzotta <gabriele.mzt@...il.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"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

On Friday 18 March 2016 18:57:33 Andrei Borzenkov wrote:
> 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>

So that means that you cannot reproduce it anymore. Anyway, if you get
it again, let us know.

-- 
Pali Rohár
pali.rohar@...il.com