Re: [PATCH] pwm_backlight: pass correct brightness to callback
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From: Thierry Reding <hidden>
Date: 2012-07-09 05:10:10
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On Mon, Jul 09, 2012 at 01:21:40PM +0900, Alexandre Courbot wrote:
pwm_backlight_update_status calls two callbacks before and after applying the new PWM settings. However, the brightness scale is completely changed in between if brightness levels are used. This patch ensures that both callbacks are passed brightness values of the same meaning. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> --- drivers/video/backlight/pwm_bl.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
I had to actually read this patch a number of times and then realized I was completely missing the context. Looking at the whole function makes it more obvious what you mean. However I think it'd be much clearer if we just passed the value of bl->props.brightness into the callbacks, that way we can avoid the additional variable. Thierry
quoted hunk ↗ jump to hunk
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 057389d..dd4d24d 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c@@ -39,6 +39,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); int brightness = bl->props.brightness; + int pwm_brightness; int max = bl->props.max_brightness; if (bl->props.power != FB_BLANK_UNBLANK)@@ -55,13 +56,14 @@ static int pwm_backlight_update_status(struct backlight_device *bl) pwm_disable(pb->pwm); } else { if (pb->levels) { - brightness = pb->levels[brightness]; + pwm_brightness = pb->levels[brightness]; max = pb->levels[max]; - } + } else + pwm_brightness = brightness; - brightness = pb->lth_brightness + - (brightness * (pb->period - pb->lth_brightness) / max); - pwm_config(pb->pwm, brightness, pb->period); + pwm_brightness = pb->lth_brightness + + (pwm_brightness * (pb->period - pb->lth_brightness) / max); + pwm_config(pb->pwm, pwm_brightness, pb->period); pwm_enable(pb->pwm); }-- 1.7.11.1
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