linux-kernel - Re: [PATCH] platform/x86: fujitsu-laptop: Fix radio LED detection

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Date:   Wed, 25 Oct 2017 17:03:56 +1030
From:   Jonathan Woithe <jwoithe@...t42.net>
To:     Micha?? K??pie?? <kernel@...pniu.pl>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>, Harvey <harv@....de>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/x86: fujitsu-laptop: Fix radio LED detection

On Wed, Oct 25, 2017 at 06:29:46AM +0200, Micha?? K??pie?? wrote:
> Radio LED detection method implemented in commit 4f62568c1fcf
> ("fujitsu-laptop: Support radio LED") turned out to be incorrect as it
> causes a radio LED to be erroneously detected on a Fujitsu Lifebook E751
> which has a slide switch (and thus no radio LED).  Use bit 17 of
> flags_supported (the value returned by method S000 of ACPI device
> FUJ02E3) to determine whether a radio LED is present as it seems to be a
> more reliable indicator, based on comparing DSDT tables of four Fujitsu
> Lifebook models (E744, E751, S7110, S8420).
> 
> Reported-by: Heinrich Siebmanns <harv@....de>
> Signed-off-by: Micha?? K??pie?? <kernel@...pniu.pl>

This seems to be a reasonable approach given the most recent set of
observations.  Assuming it tests ok on the E751:

  Reviewed-by: Jonathan Woithe <jwoithe@...t42.net>

Regards
  jonathan

> ---
> I do not have a Fujitsu laptop with a radio LED for testing, so I was
> only able to check that this patch still does not cause a radio LED to
> be detected on a Lifebook S7020.
> 
> Harvey, could you please try this patch on your Lifebook E751 and see
> whether the log messages you reported disappear?  I will be happy to
> assist you off-list in case you need help with it.
> 
>  drivers/platform/x86/fujitsu-laptop.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
> index 56a8195096a2..2cfbd3fa5136 100644
> --- a/drivers/platform/x86/fujitsu-laptop.c
> +++ b/drivers/platform/x86/fujitsu-laptop.c
> @@ -691,6 +691,7 @@ static enum led_brightness eco_led_get(struct led_classdev *cdev)
>  
>  static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  {
> +	struct fujitsu_laptop *priv = acpi_driver_data(device);
>  	struct led_classdev *led;
>  	int result;
>  
> @@ -724,12 +725,15 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  	}
>  
>  	/*
> -	 * BTNI bit 24 seems to indicate the presence of a radio toggle
> -	 * button in place of a slide switch, and all such machines appear
> -	 * to also have an RF LED.  Therefore use bit 24 as an indicator
> -	 * that an RF LED is present.
> +	 * Some Fujitsu laptops have a radio toggle button in place of a slide
> +	 * switch and all such machines appear to also have an RF LED.  Based on
> +	 * comparing DSDT tables of four Fujitsu Lifebook models (E744, E751,
> +	 * S7110, S8420; the first one has a radio toggle button, the other
> +	 * three have slide switches), bit 17 of flags_supported (the value
> +	 * returned by method S000 of ACPI device FUJ02E3) seems to indicate
> +	 * whether given model has a radio toggle button.
>  	 */
> -	if (call_fext_func(device, FUNC_BUTTONS, 0x0, 0x0, 0x0) & BIT(24)) {
> +	if (priv->flags_supported & BIT(17)) {
>  		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
>  		if (!led)
>  			return -ENOMEM;
> -- 
> 2.14.2