On Wed, 11 Nov 2015, "Shih-Yuan Lee (FourDollars)" <sylee@xxxxxxxxxxxxx> wrote: > Take Dell XPS 13 (2015) as an example. The vbt min 10 out of [0..255]. > The PWM max is 937 so the corresponding PWM min is 37 (10*937/256). > This commit makes the sysfs brightness 1 map to the PWM brightness 37 > and 100 map to the PWM brightness 937. > > Signed-off-by: Shih-Yuan Lee (FourDollars) <sylee@xxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_panel.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c > index a24df35..8652ce2 100644 > --- a/drivers/gpu/drm/i915/intel_panel.c > +++ b/drivers/gpu/drm/i915/intel_panel.c > @@ -1207,11 +1207,12 @@ static int intel_backlight_device_register(struct intel_connector *connector) > memset(&props, 0, sizeof(props)); > props.type = BACKLIGHT_RAW; > > - /* > - * Note: Everything should work even if the backlight device max > - * presented to the userspace is arbitrarily chosen. > - */ > - props.max_brightness = panel->backlight.max; > + /* Setting max to fixed 100 if the range is large enough. */ > + if (panel->backlight.max > panel->backlight.min + 99) > + props.max_brightness = 100; > + else > + props.max_brightness = panel->backlight.max - panel->backlight.min; No, the intention is to have a fixed 0..100 range no ifs no buts. > + > props.brightness = scale_hw_to_user(connector, > panel->backlight.level, > props.max_brightness); > @@ -1414,6 +1415,8 @@ static u32 get_backlight_min_vbt(struct intel_connector *connector) > struct drm_device *dev = connector->base.dev; > struct drm_i915_private *dev_priv = dev->dev_private; > struct intel_panel *panel = &connector->panel; > + u32 pwm_min; > + u32 pwm_step; > int min; > > WARN_ON(panel->backlight.max == 0); > @@ -1432,7 +1435,22 @@ static u32 get_backlight_min_vbt(struct intel_connector *connector) > } > > /* vbt value is a coefficient in range [0..255] */ > - return scale(min, 0, 255, 0, panel->backlight.max); > + pwm_min = scale(min, 0, 255, 0, panel->backlight.max); > + > + /* Calculate the PWM step */ > + if (panel->backlight.max > pwm_min + 99) > + pwm_step = scale(1, 0, 99, 0, panel->backlight.max - pwm_min); > + else > + pwm_step = 1; > + > + /* > + * Because sysfs brightness 0 is used to turn off the backlight, we need step > + * down a little bit to make sysfs brightness 1 match the lowest brightness. > + */ > + if (pwm_min >= pwm_step) > + pwm_min -= pwm_step; > + > + return pwm_min; This is getting tricky, and you assume too much. Currently, 0 means off if dev_priv->vbt.backlight.min_brightness == 0 or the panel is eDP. LVDS panels with non-zero min brightness aren't switched off with 0 brightness. Pardon my bluntness, but I'm starting to feel like you just want to get a patch in. Take my word for it, backlight is not where you should get started. BR, Jani. > } > > static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unused) -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
