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Commit bee460be authored by Jason Stubbs's avatar Jason Stubbs Committed by Matthew Garrett
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platform: samsung_laptop: fix samsung brightness min/max calculations 



The min_brightness value of the sabi_config is incorrectly used in brightness
calculations. For the config where min_brightness = 1 and max_brightness = 8,
the user visible range should be 0 to 7 with hardware being set in the range
of 1 to 8. What is actually happening is that the user visible range is 0 to
8 with hardware being set in the range of -1 to 7.

This patch fixes the above issue as well as a miscalculation that would occur
in the case of min_brightness > 1.

Signed-off-by: default avatarJason Stubbs <jasonbstubbs@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
parent 093ed561

drivers/platform/x86/samsung-laptop.c

+6 −3
Original line number Diff line number Diff line
@@ -370,15 +370,17 @@ static u8 read_brightness(void) 
				  &sretval);

	if (!retval) {

		user_brightness = sretval.retval[0];

		if (user_brightness != 0)

		if (user_brightness > sabi_config->min_brightness)

			user_brightness -= sabi_config->min_brightness;

		else

			user_brightness = 0;

	}

	return user_brightness;

}



static void set_brightness(u8 user_brightness)

{

	u8 user_level = user_brightness - sabi_config->min_brightness;

	u8 user_level = user_brightness + sabi_config->min_brightness;



	sabi_set_command(sabi_config->commands.set_brightness, user_level);

}
@@ -811,7 +813,8 @@ static int __init samsung_init(void) 
	/* create a backlight device to talk to this one */

	memset(&props, 0, sizeof(struct backlight_properties));

	props.type = BACKLIGHT_PLATFORM;

	props.max_brightness = sabi_config->max_brightness;

	props.max_brightness = sabi_config->max_brightness -

				sabi_config->min_brightness;

	backlight_device = backlight_device_register("samsung", &sdev->dev,

						     NULL, &backlight_ops,

						     &props);