On Wed, 2017-05-03 at 17:28 -0700, Puthikorn Voravootivat wrote: > This patch enables dynamic backlight by default for eDP > panel that supports this feature via DPCD register and > set minimum / maximum brightness to 0% and 100% of the > normal brightness. I read the link that you shared last time, should there be a switch for a feature like this that can affect image quality? Should this be a decision in the kernel with no provision to turn off/on? -DK > > Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 39 ++++++++++++++++++++++----- > 1 file changed, 33 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > index 5ef3ade7c40e..7d323af96636 100644 > --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > @@ -97,10 +97,27 @@ intel_dp_aux_set_backlight(struct intel_connector *connector, u32 level) > } > } > > +/* > + * Set minimum / maximum dynamic brightness percentage. This value is expressed > + * as the percentage of normal brightness in 5% increments. > + */ > +static void > +intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp, > + u32 min, u32 max) > +{ > + u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5) }; > + > + if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET, > + dbc, sizeof(dbc) < 0)) { > + DRM_DEBUG_KMS("Failed to write aux DBC brightness level\n"); > + } > +} > + > static void intel_dp_aux_enable_backlight(struct intel_connector *connector) > { > struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); > uint8_t dpcd_buf = 0; > + uint8_t new_dpcd_buf = 0; > uint8_t edp_backlight_mode = 0; > > if (drm_dp_dpcd_readb(&intel_dp->aux, > @@ -110,18 +127,15 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) > return; > } > > + new_dpcd_buf = dpcd_buf; > edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; > > switch (edp_backlight_mode) { > case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM: > case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET: > case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT: > - dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; > - dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; > - if (drm_dp_dpcd_writeb(&intel_dp->aux, > - DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf) < 0) { > - DRM_DEBUG_KMS("Failed to write aux backlight mode\n"); > - } > + new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; > + new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; > break; > > /* Do nothing when it is already DPCD mode */ > @@ -130,6 +144,19 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) > break; > } > > + if (intel_dp->edp_dpcd[2] & DP_EDP_DYNAMIC_BACKLIGHT_CAP) { > + new_dpcd_buf |= DP_EDP_DYNAMIC_BACKLIGHT_ENABLE; > + intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0, 100); > + DRM_DEBUG_KMS("Enable dynamic brightness.\n"); > + } > + > + if (new_dpcd_buf != dpcd_buf) { > + if (drm_dp_dpcd_writeb(&intel_dp->aux, > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) { > + DRM_DEBUG_KMS("Failed to write aux backlight mode\n"); > + } > + } > + > set_aux_backlight_enable(intel_dp, true); > } > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel