linux-kernel - Re: [PATCH 03/15] samsung-laptop: don't handle backlight if handled by acpi/video

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Message-ID: <CANq1E4QoBk1oPT8z2-2hHeXkKa8K34hhwZrMqXOknmtEY1ghBw@mail.gmail.com>
Date:	Wed, 23 Nov 2011 17:01:26 +0100
From:	David Herrmann <dh.herrmann@...glemail.com>
To:	Corentin Chary <corentincj@...aif.net>
Cc:	platform-driver-x86@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Matthew Garrett <mjg@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/15] samsung-laptop: don't handle backlight if handled
 by acpi/video

Hi Corentin

On Tue, Nov 22, 2011 at 11:02 PM, Corentin Chary <corentincj@...aif.net> wrote:
> samsung-laptop is not at all related to ACPI, but since this interface
> is not documented at all, and the driver has to use it at load to
> understand how it works on the laptop, I think it's a good idea to
> disable it if a better solution is available.
>
> Signed-off-by: Corentin Chary <corentincj@...aif.net>
> ---
>  drivers/platform/x86/samsung-laptop.c |   20 ++++++++++++++++++--
>  1 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
> index be96910..49933d2 100644
> --- a/drivers/platform/x86/samsung-laptop.c
> +++ b/drivers/platform/x86/samsung-laptop.c
> @@ -21,6 +21,7 @@
>  #include <linux/dmi.h>
>  #include <linux/platform_device.h>
>  #include <linux/rfkill.h>
> +#include <linux/acpi.h>
>
>  /*
>  * This driver is needed because a number of Samsung laptops do not hook
> @@ -230,6 +231,7 @@ struct samsung_laptop {
>        struct backlight_device *backlight_device;
>        struct rfkill *rfk;
>
> +       bool handle_backlight;
>        bool has_stepping_quirk;
>  };
>
> @@ -616,6 +618,9 @@ static int __init samsung_backlight_init(struct samsung_laptop *samsung)
>        struct backlight_device *bd;
>        struct backlight_properties props;
>
> +       if (!samsung->handle_backlight)
> +               return 0;
> +
>        memset(&props, 0, sizeof(struct backlight_properties));
>        props.type = BACKLIGHT_PLATFORM;
>        props.max_brightness = samsung->config->max_brightness -
> @@ -698,7 +703,8 @@ static void __init samsung_sabi_selftest(struct samsung_laptop *samsung,
>        printk(KERN_DEBUG "ifaceP = 0x%08x\n", ifaceP);
>        printk(KERN_DEBUG "sabi_iface = %p\n", samsung->sabi_iface);
>
> -       test_backlight(samsung);
> +       if (samsung->handle_backlight)
> +               test_backlight(samsung);
>        test_wireless(samsung);
>
>        sabi_get_command(samsung, config->commands.get_brightness, &sretval);
> @@ -771,7 +777,8 @@ static int __init samsung_sabi_init(struct samsung_laptop *samsung)
>        }
>
>        /* Check for stepping quirk */
> -       check_for_stepping_quirk(samsung);
> +       if (samsung->handle_backlight)
> +               check_for_stepping_quirk(samsung);
>
>  exit:
>        if (ret)
> @@ -1059,6 +1066,15 @@ static int __init samsung_init(void)
>                return -ENOMEM;
>
>        mutex_init(&samsung->sabi_mutex);
> +       samsung->handle_backlight = true;
> +
> +#ifdef CONFIG_ACPI
> +       /* Don't handle backlight here if the acpi video already handle it */
> +       if (acpi_video_backlight_support()) {
> +               pr_info("Backlight controlled by ACPI video driver\n");
> +               samsung->handle_backlight = false;
> +       }
> +#endif
>
>        ret = samsung_platform_init(samsung);
>        if (ret)
> --
> 1.7.5.4

My Samsung model has an intel card which previously did not support
the acpi video backlight so I needed the samsung driver.
However, with this patch I couldn't find the samsung backlight and so
I tried the intel back light again and now it works.
So:
Tested-by: David Herrmann <dh.herrmann@...glemail.com>

My model is Samsung N210 btw.

Regards
David
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