On Tue, 17 Dec 2024 at 19:21, Maxime Ripard <mripard@xxxxxxxxxx> wrote: > > 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? LT9611 is actually tested, VC4 is only compile-tested. Should I put an RFT tag? -- With best wishes Dmitry
