RE: [PATCH] drm/vc4: Enable the DSI module and link before other enables.

From: Eric Anholt
Date: Thu Jun 21 2018 - 19:19:32 EST


Kevin Quigley <kevin@xxxxxxxxxxxxxx> writes:

> Hi,
>
> When we talk about control bus enable and video transfer enable for
> DSI, there is a mode in which control commands can be sent,
> interleaved with the video. This is often done at the end-of-frame
> and/or end of line. I've seen this handled in some other DSI device
> drivers. In these cases, the driver has to look at the frame timing
> in the video and carefully select the number of control bytes which
> can be sent during the blanking periods. The number of bytes which
> can be sent, is very much dependant on the panel-size and clock
> frequencies... (which determines the blanking time). I'm not sure how
> widely this is a feature in the DSI encoder HW, and/or implemented
> purely in the drivers.

That scheduling is done by the VC4 DSI encoder.

> To conclude: I think that DSI encoder devices need to be able to
> support sending control data (LPDA) - concurrently with video frames.

I believe that should work already.

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