[Intel-gfx] [PATCH v2] drm/i915/display: program audio CDCLK-TS for keepalives

[Kai Vehmanen]

Hi,

On Wed, 6 Oct 2021, Ville Syrjälä wrote:

> On Mon, Sep 13, 2021 at 07:40:04PM +0300, Kai Vehmanen wrote:
> > XE_LPD display adds support for display audio codec keepalive feature.
> > This feature works also when display codec is in D3 state and the audio
> > link is off (BCLK off). To enable this functionality, display driver
> > must update the AUD_TS_CDCLK_M/N registers whenever CDCLK is changed.
> > Actual timestamps are generated only when the audio codec driver
> > specifically enables the KeepAlive (KAE) feature.
[...]
> > +	if (refclk == 24000)
> > +		aud_ts->m = 12;
> 
> Wasn't there a single exception to this rule? Ie. should this be 
> if (refclk == 24000 && cdclk != something) ?

ack. I had a discussion with hw folks on this and concluded we can go
with the simple formula.

Br, Kai