Hi, On Tue, Dec 17, 2024 at 02:40:22AM +0200, Dmitry Baryshkov wrote: > While porting lt9611 DSI-to-HDMI bridge driver to use HDMI Connector > framework, I stumbled upon an issue while handling the Audio InfoFrames. > The HDMI codec callbacks weren't receiving the drm_atomic_state, so > there was no simple way to get the drm_connector that stayed at the end > of the bridge chain. At the same point the drm_hdmi_connector functions > expected to get drm_connector instance. > > While looking for a way to solve the issue, I stumbled upon several > deficiencies in existing hdmi_codec_ops implementations. Only few of the > implementations were able to handle codec's 'plugged' callback. One > third of the drivers didn't implement the get_eld() callback. > > Most of the issues can be solved if drm_connector handles > hdmi-audio-codec on its own, delegating functionality to the actual > implementation, be it a driver that implements drm_connector or > drm_bridge. > > Implement such high-level framework, adding proper support for Audio > InfoFrame generation to the LT9611 driver. > > Several design decisions to be kept in mind: > > - drm_connector_hdmi_codec is kept as simple as possible. It implements > generic functionality (ELD, hotplug, registration). > > - drm_hdmi_connector sets up HDMI codec device if the connector > is setup correspondingly (either I2S or S/PDIF is marked as > supported). > > - drm_bridge_connector provides a way to link HDMI audio codec > funcionality in the drm_bridge with the drm_connector_hdmi_codec > framework. > > - It might be worth reverting the no_i2s_capture / no_spdif_capture > bits. Only TDA889x driver sets them, while it's safe to assume that > most of HDMI / DP devices do not support ARC / capture. I think the > drivers should opt-in capture support rather than having to opt-out of > it. Sorry if this isn't clear to me and I'm quite late to the party, but did you test this on vc4 with both a pi3 and pi4, or was it just compile tested? Maxime
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