[Intel-gfx] [PATCH 3/5] drm/i915: Support dynamic backlight via DPCD register
Jani Nikula
jani.nikula at linux.intel.com
Thu Mar 9 10:10:27 UTC 2017
On Wed, 08 Mar 2017, Puthikorn Voravootivat <puthik at chromium.org> 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.
>
> Signed-off-by: Puthikorn Voravootivat <puthik at chromium.org>
> ---
> drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 31 +++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> index 16cd1265d264..643b604be2de 100644
> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> @@ -97,10 +97,24 @@ 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)
static void
intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp,
u32 min, u32 max)
would be preferable indentation.
> +{
u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5)};
drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
dbc, sizeof(dbc));
> + drm_dp_dpcd_writeb(&intel_dp->aux,
> + DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET, min / 5);
> + drm_dp_dpcd_writeb(&intel_dp->aux,
> + DP_EDP_DBC_MAXIMUM_BRIGHTNESS_SET, max / 5);
> +}
> +
> 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;
>
> set_aux_backlight_enable(intel_dp, true);
> @@ -110,15 +124,14 @@ 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:
> - dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> - dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> - drm_dp_dpcd_writeb(&intel_dp->aux,
> - DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);
> + new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> + new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> break;
>
> /* Do nothing in these cases */
> @@ -127,6 +140,16 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
> default:
> 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);
> + }
> +
> + if (new_dpcd_buf != dpcd_buf) {
> + drm_dp_dpcd_writeb(&intel_dp->aux,
> + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf);
> + }
> }
>
> static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
--
Jani Nikula, Intel Open Source Technology Center
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