Platform: Detect samsung laptop quirk when initial level is zero
On Fri, Dec 02, 2011 at 03:17:24PM -0600, Seth Forshee wrote:
> From: John Serock <john.serock@gmail.com>
>
> This patch depends on the "Platform: Brightness quirk for samsung
> laptop driver" patch from Jason Stubbs. This patch adds a check for an
> initial brightness level of 0; if the level is 0, this patch changes
> the brightness level to 1 before the driver attempts to detect the
> brightness quirk.
>
> The Samsung N150 netbook experiences the brightness quirk. Without
> Jason's patch, the only brightness levels available on the N150 are 0,
> 1, and 8. This patch ensures that, when the initial brightness level
> is 0, the samsang-laptop driver detects the brightness quirk on the
> N150, thereby making brightness levels 0 through 8 available.
>
> Signed-off-by: John Serock <john.serock@gmail.com>
> Acked-by: Jason Stubbs <jasonbstubbs@gmail.com>
> Signed-off-by: Matthew Garrett <mjg@redhat.com>
>
> (cherry picked from commit ba05b237372bad82533d1f717569d1d817ff3c27)
> BugLink: http://bugs.launchpad.net/bugs/810093
> Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
> ---
> drivers/platform/x86/samsung-laptop.c | 10 ++++++++--
> 1 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
> index c32dc39..e553486 100644
> --- a/drivers/platform/x86/samsung-laptop.c
> +++ b/drivers/platform/x86/samsung-laptop.c
> @@ -404,8 +404,9 @@ static int get_brightness(struct backlight_device *bd)
>
> static void check_for_stepping_quirk(void)
> {
> - u8 initial_level = read_brightness();
> + u8 initial_level;
> u8 check_level;
> + u8 orig_level = read_brightness();
>
> /*
> * Some laptops exhibit the strange behaviour of stepping toward
> @@ -414,6 +415,11 @@ static void check_for_stepping_quirk(void)
> * around in set_brightness.
> */
>
> + if (orig_level == 0)
> + set_brightness(1);
> +
> + initial_level = read_brightness();
> +
He could have avoid calling read_brightness() twice in the case of
orig_level !=0, minor/harmless thing anyway...
Acked-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Platform: Detect samsung laptop quirk when initial level is zero
