diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c index c0ce6d3dc505..7468b570a72a 100644 --- a/drivers/gpu/drm/i915/display/intel_hdmi.c +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c @@ -2240,6 +2240,25 @@ static bool intel_hdmi_is_cloned(const struct intel_crtc_state *crtc_state) !is_power_of_2(crtc_state->uapi.encoder_mask); } +static bool source_supports_scrambling(struct intel_encoder *encoder) +{ + /* + * Gen 10+ support HDMI 2.0 : the max tmds clock is 594MHz, and + * scrambling is supported. + * But there seem to be cases where certain platforms that support + * HDMI 2.0, have an HDMI1.4 retimer chip, and the max tmds clock is + * capped by VBT to less than 340MHz. + * + * In such cases when an HDMI2.0 sink is connected, it creates a + * problem : the platform and the sink both support scrambling but the + * HDMI 1.4 retimer chip doesn't. + * + * So go for scrambling, based on the max tmds clock taking into account, + * restrictions coming from VBT. + */ + return intel_hdmi_source_max_tmds_clock(encoder) > 340000; +} + int intel_hdmi_compute_config(struct intel_encoder *encoder, struct intel_crtc_state *pipe_config, struct drm_connector_state *conn_state) @@ -2302,7 +2321,7 @@ int intel_hdmi_compute_config(struct intel_encoder *encoder, pipe_config->lane_count = 4; - if (scdc->scrambling.supported && DISPLAY_VER(dev_priv) >= 10) { + if (scdc->scrambling.supported && source_supports_scrambling(encoder)) { if (scdc->scrambling.low_rates) pipe_config->hdmi_scrambling = true;