linux-kernel - Re: [PATCH v2] dell-laptop: Fix keyboard led max_brightness property for Dell Latitude E6410

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Date:   Wed, 18 Oct 2017 13:00:10 -0700
From:   Darren Hart <dvhart@...radead.org>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     Matthew Garrett <mjg59@...f.ucam.org>,
        Andy Shevchenko <andy@...radead.org>,
        "Gabriel M. Elder" <gabriel@...gnowsys.com>,
        Gabriele Mazzotta <gabriele.mzt@...il.com>,
        Mario.Limonciello@...l.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] dell-laptop: Fix keyboard led max_brightness property
 for Dell Latitude E6410

On Wed, Oct 18, 2017 at 08:06:01PM +0200, Pali Rohár wrote:
> This machine reports number of keyboard backlight led levels, instead of
> value of the last led level index. Therefore max_brightness properly needs
> to be subtracted by 1 to match led max_brightness API.
> 
> Signed-off-by: Pali Rohár <pali.rohar@...il.com>
> Reported-by: Gabriel M. Elder <gabriel@...gnowsys.com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=196913
> ---
> Changes since v1:
> * Update kbd_info.levels at initialization time based on quirk

This looks much cleaner IMO, thanks.

> ---
>  drivers/platform/x86/dell-laptop.c |   17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
> index f42159f..3f9be8a 100644
> --- a/drivers/platform/x86/dell-laptop.c
> +++ b/drivers/platform/x86/dell-laptop.c
> @@ -49,6 +49,7 @@
>  
>  struct quirk_entry {
>  	u8 touchpad_led;
> +	u8 kbd_led_num_of_levels_instead_of_last_index;

OK, I forgot to comment on this one :-)

A name should be descriptive, but that's just too much. So let's use something
shorter, and add a comment if one is really needed to explain what it is.
Something like:

u8 kbd_led_reports_num_levels is shorter, but still awfully long.

u8 kbd_led_num_levels  is shorter, but obviously looks like it should be the
levels value instead of a bool. So the above is probably best.


>  
>  	int needs_kbd_timeouts;
>  	/*
> @@ -79,6 +80,10 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
>  	.kbd_timeouts = { 0, 5, 15, 60, 5 * 60, 15 * 60, -1 },
>  };
>  
> +static struct quirk_entry quirk_dell_latitude_e6410 = {
> +	.kbd_led_num_of_levels_instead_of_last_index = 1,
> +};
> +
>  static struct platform_driver platform_driver = {
>  	.driver = {
>  		.name = "dell-laptop",
> @@ -280,6 +285,15 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
>  		},
>  		.driver_data = &quirk_dell_xps13_9333,
>  	},
> +	{
> +		.callback = dmi_matched,
> +		.ident = "Dell Latitude E6410",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6410"),
> +		},
> +		.driver_data = &quirk_dell_latitude_e6410,
> +	},
>  	{ }
>  };
>  
> @@ -1200,6 +1214,9 @@ static int kbd_get_info(struct kbd_info *info)
>  	units = (buffer->output[2] >> 8) & 0xFF;
>  	info->levels = (buffer->output[2] >> 16) & 0xFF;
>  
> +	if (quirks && quirks->kbd_led_num_of_levels_instead_of_last_index && info->levels)
> +		info->levels--;
> +
>  	if (units & BIT(0))
>  		info->seconds = (buffer->output[3] >> 0) & 0xFF;
>  	if (units & BIT(1))
> -- 
> 1.7.9.5
> 
> 

-- 
Darren Hart
VMware Open Source Technology Center