<div dir="ltr"><div class="gmail_extra"> <div class="gmail_quote">On Fri, Jun 2, 2017 at 11:25 AM, Pandiyan, Dhinakaran <<a href="mailto:dhinakaran.pandiyan@intel.com" target="_blank" class="gmail-cremed cremed">dhinakaran.pandiyan@intel.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Fri, 2017-05-26 at 18:42 -0700, Puthikorn Voravootivat wrote: <div><div class="gmail-h5">> This patch adds option to enable dynamic backlight 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 <<a href="mailto:puthik@chromium.org" class="gmail-cremed cremed">puthik@chromium.org</a>> > --- > drivers/gpu/drm/i915/i915_params.c | 5 ++++ > drivers/gpu/drm/i915/i915_params.h | 3 +- > drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 42 ++++++++++++++++++++++----- > 3 files changed, 41 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c > index 3758ae1f11b4..ce033d58134e 100644 > --- a/drivers/gpu/drm/i915/i915_params.c > +++ b/drivers/gpu/drm/i915/i915_params.c > @@ -65,6 +65,7 @@ struct i915_params i915 __read_mostly = { > .inject_load_failure = 0, > .enable_dpcd_backlight = -1, > .enable_gvt = false, > + .enable_dbc = false, > }; > > module_param_named(modeset, i915.modeset, int, 0400); > @@ -254,3 +255,7 @@ MODULE_PARM_DESC(enable_dpcd_backlight, > module_param_named(enable_gvt, i915.enable_gvt, bool, 0400); > MODULE_PARM_DESC(enable_gvt, > "Enable support for Intel GVT-g graphics virtualization host support(default:false)"); > + > +module_param_named_unsafe(enable_dbc, i915.enable_dbc, bool, 0600); > +MODULE_PARM_DESC(enable_dbc, > + "Enable support for dynamic backlight control (default:false)"); > diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h > index ac02efce6e22..2de3e2850b54 100644 > --- a/drivers/gpu/drm/i915/i915_params.h > +++ b/drivers/gpu/drm/i915/i915_params.h > @@ -67,7 +67,8 @@ > func(bool, nuclear_pageflip); \ > func(bool, enable_dp_mst); \ > func(int, enable_dpcd_backlight); \ > - func(bool, enable_gvt) > + func(bool, enable_gvt); \ > + func(bool, enable_dbc) > > #define MEMBER(T, member) T member > struct i915_params { > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > index c89aae804659..f55af41ce3bd 100644 > --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > @@ -100,11 +100,26 @@ 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 edp_backlight_mode = 0; > + uint8_t dpcd_buf, new_dpcd_buf, edp_backlight_mode; > > if (drm_dp_dpcd_readb(&intel_dp->aux, > DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) { > @@ -113,18 +128,15 @@ 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 */ > @@ -133,6 +145,20 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) > break; > } > > + if (i915.enable_dbc && > + (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"); > + } > + </div></div>Just curious, does DBC require DP AUX brightness control? </blockquote><div>No. Here is quote from the spec.</div><div>"The Dynamic Backlight Control (DBC) and color engine modes are not listed in Table 10-1,</div><div>because when they are available, they are available for all supported modes." </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> -DK <div class="gmail-HOEnZb"><div class="gmail-h5"> > + 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); > intel_dp_aux_set_backlight(connector, connector->panel.backlight.level); > } </div></div></blockquote></div> </div></div>