TCON tend to have better brightness scaling with lower PWM frequency. This patch set the divider to highest value to lower the PWM frequency.
Signed-off-by: Puthikorn Voravootivat <[email protected]> --- drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c index 643b604be2de..32b426006a6a 100644 --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c @@ -116,6 +116,7 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) uint8_t dpcd_buf = 0; uint8_t new_dpcd_buf = 0; uint8_t edp_backlight_mode = 0; + bool freq_cap = false; set_aux_backlight_enable(intel_dp, true); @@ -146,10 +147,20 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0, 100); } + /* Use highest frequency divider if supported */ + freq_cap = intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP; + if (freq_cap) + new_dpcd_buf |= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE; + if (new_dpcd_buf != dpcd_buf) { drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf); } + + if (freq_cap) { + drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_FREQ_SET, + 0xff); + } } static void intel_dp_aux_disable_backlight(struct intel_connector *connector) -- 2.12.0.246.ga2ecc84866-goog _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
