Hi, On Fri, Sep 06, 2024 at 04:17:40AM GMT, Cristian Ciocaltea wrote: > +static enum drm_connector_status > +dw_hdmi_qp_bridge_detect(struct drm_bridge *bridge) > +{ > + struct dw_hdmi_qp *hdmi = bridge->driver_private; > + enum drm_connector_status status; > + > + status = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data); > + > + dev_dbg(hdmi->dev, "%s conn=%d scramb=%d\n", __func__, > + status == connector_status_connected, hdmi->scramb_enabled); > + > + if (hdmi->scramb_enabled) { > + cancel_delayed_work_sync(&hdmi->scramb_work); > + > + if (status == connector_status_connected) > + dw_hdmi_qp_check_and_set_scramb(hdmi); > + } > + > + return status; > +} Unfortunately, that won't work. The HDMI Spec has (HDMI 2.0, Section 6.1.3.1 - Scrambling Control): The minimum time period between the write to the Scrambling_Enable bit, and the transmission of a scrambled video signal is not specified; however the Source shall not begin transmission of a scrambled video signal before writing a 1 to the Scrambling_Enable bit. The maximum time period between the write to the Scrambling_Enable bit and the transmission of a scrambled video signal shall be 100 ms. So you need to disable the output and enable it again. vc4 does just that, you can have a look here: https://elixir.bootlin.com/linux/v6.10.9/source/drivers/gpu/drm/vc4/vc4_hdmi.c#L410 Maxime
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