linux-kernel - Re: [PATCH] platform/x86: intel-hid: Wake up Dell Latitude 7275 from suspend-to-idle

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Date:   Mon, 31 Jul 2017 23:46:28 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     platform-driver-x86@...r.kernel.org
Cc:     Darren Hart <dvhart@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Jérôme de Bretagne 
        <jerome.debretagne@...il.com>,
        Mario Limonciello <mario.limonciello@...l.com>,
        Alex Hung <alex.hung@...onical.com>
Subject: Re: [PATCH] platform/x86: intel-hid: Wake up Dell Latitude 7275 from suspend-to-idle

On Friday, July 28, 2017 02:06:36 AM Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> On Dell Latitude 7275 the 5-button array is not exposed in the
> ACPI tables, but still notifies are sent to the Intel HID device
> object (device ID INT33D5) in response to power button actions while
> suspended to idle.  However, they are currently ignored as the
> intel-hid driver is not prepared to take care of them.
> 
> As a result, power button wakeup from suspend-to-idle doesn't work
> on this platform, but suspend-to-idle is the only reliable suspend
> variant on it (the S3 implementation in the platform firmware turns
> out to be broken), so it would be good to handle it properly.
> 
> For this reason, add an upfront check against the power button press
> event (0xCE) to notify_handler() in the wakeup mode which allows it
> to catch the power button wakeup notification on the affected
> platform (even though priv->array is NULL on it) and should not
> change the behavior on platforms with priv->array present (because
> priv->array contains the event in question in those cases).
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=196115
> Tested-by: Jérôme de Bretagne <jerome.debretagne@...il.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Please note that this change is requisite for

https://patchwork.kernel.org/patch/9873159/

so are there any objections or concerns?

> ---
>  drivers/platform/x86/intel-hid.c |   17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> Index: linux-pm/drivers/platform/x86/intel-hid.c
> ===================================================================
> --- linux-pm.orig/drivers/platform/x86/intel-hid.c
> +++ linux-pm/drivers/platform/x86/intel-hid.c
> @@ -203,15 +203,26 @@ static void notify_handler(acpi_handle h
>  	acpi_status status;
>  
>  	if (priv->wakeup_mode) {
> +		/*
> +		 * Needed for wakeup from suspend-to-idle to work on some
> +		 * platforms that don't expose the 5-button array, but still
> +		 * send notifies with the power button event code to this
> +		 * device object on power button actions while suspended.
> +		 */
> +		if (event == 0xce)
> +			goto wakeup;
> +
>  		/* Wake up on 5-button array events only. */
>  		if (event == 0xc0 || !priv->array)
>  			return;
>  
> -		if (sparse_keymap_entry_from_scancode(priv->array, event))
> -			pm_wakeup_hard_event(&device->dev);
> -		else
> +		if (!sparse_keymap_entry_from_scancode(priv->array, event)) {
>  			dev_info(&device->dev, "unknown event 0x%x\n", event);
> +			return;
> +		}
>  
> +wakeup:
> +		pm_wakeup_hard_event(&device->dev);
>  		return;
>  	}
>  
>