diff options
| -rw-r--r-- | drivers/gpu/drm/i915/i915_params.c | 7 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_params.h | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 61 |
3 files changed, 63 insertions, 7 deletions
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c index 14e2c2e57f96..5b5ab15d191f 100644 --- a/drivers/gpu/drm/i915/i915_params.c +++ b/drivers/gpu/drm/i915/i915_params.c @@ -63,7 +63,7 @@ struct i915_params i915 __read_mostly = { .huc_firmware_path = NULL, .enable_dp_mst = true, .inject_load_failure = 0, - .enable_dpcd_backlight = false, + .enable_dpcd_backlight = -1, .enable_gvt = false, }; @@ -246,9 +246,10 @@ MODULE_PARM_DESC(enable_dp_mst, module_param_named_unsafe(inject_load_failure, i915.inject_load_failure, uint, 0400); MODULE_PARM_DESC(inject_load_failure, "Force an error after a number of failure check points (0:disabled (default), N:force failure at the Nth failure check point)"); -module_param_named(enable_dpcd_backlight, i915.enable_dpcd_backlight, bool, 0600); +module_param_named_unsafe(enable_dpcd_backlight, i915.enable_dpcd_backlight, int, 0600); MODULE_PARM_DESC(enable_dpcd_backlight, - "Enable support for DPCD backlight control (default:false)"); + "Enable support for DPCD backlight control " + "(-1:auto (default), 0:force disable, 1:force enabled if supported"); module_param_named(enable_gvt, i915.enable_gvt, bool, 0400); MODULE_PARM_DESC(enable_gvt, diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h index febbfdbd30bd..0d6cf9138dc4 100644 --- a/drivers/gpu/drm/i915/i915_params.h +++ b/drivers/gpu/drm/i915/i915_params.h @@ -53,6 +53,7 @@ func(int, edp_vswing); \ func(int, reset); \ func(unsigned int, inject_load_failure); \ + func(int, enable_dpcd_backlight); \ /* leave bools at the end to not create holes */ \ func(bool, alpha_support); \ func(bool, enable_cmd_parser); \ @@ -66,7 +67,6 @@ func(bool, verbose_state_checks); \ func(bool, nuclear_pageflip); \ func(bool, enable_dp_mst); \ - func(bool, enable_dpcd_backlight); \ func(bool, enable_gvt) #define MEMBER(T, member) T member diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c index d2830ba3162e..fea161727c6e 100644 --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c @@ -251,15 +251,66 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector) /* Check the eDP Display control capabilities registers to determine if * the panel can support backlight control over the aux channel */ - if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP && - (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) && - !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) { + if ((intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP) && + (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) { DRM_DEBUG_KMS("AUX Backlight Control Supported!\n"); return true; } return false; } +/* + * Heuristic function whether we should use AUX for backlight adjustment or not. + * + * We should use AUX for backlight brightness adjustment if panel doesn't this + * via PWM pin or using AUX is better than using PWM pin. + * + * The heuristic to determine that using AUX pin is better than using PWM pin is + * that the panel support any of the feature list here. + * - Regional backlight brightness adjustment + * - Backlight PWM frequency set + * - More than 8 bits resolution of brightness level + * - Backlight enablement via AUX and not by BL_ENABLE pin + * + * If all above are not true, assume that using PWM pin is better. + */ +static bool +intel_dp_aux_display_control_heuristic(struct intel_connector *connector) +{ + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); + uint8_t reg_val; + + /* Panel doesn't support adjusting backlight brightness via PWN pin */ + if (!(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) + return true; + + /* Panel supports regional backlight brightness adjustment */ + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_GENERAL_CAP_3, + ®_val) != 1) { + DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n", + DP_EDP_GENERAL_CAP_3); + return false; + } + if (reg_val > 0) + return true; + + /* Panel supports backlight PWM frequency set */ + if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP) + return true; + + /* Panel supports more than 8 bits resolution of brightness level */ + if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) + return true; + + /* Panel supports enabling backlight via AUX but not by BL_ENABLE pin */ + if ((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) && + !(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP)) + return true; + + return false; + +} + int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector) { struct intel_panel *panel = &intel_connector->panel; @@ -270,6 +321,10 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector) if (!intel_dp_aux_display_control_capable(intel_connector)) return -ENODEV; + if (i915.enable_dpcd_backlight == -1 && + !intel_dp_aux_display_control_heuristic(intel_connector)) + return -ENODEV; + panel->backlight.setup = intel_dp_aux_setup_backlight; panel->backlight.enable = intel_dp_aux_enable_backlight; panel->backlight.disable = intel_dp_aux_disable_backlight; |