From mboxrd@z Thu Jan  1 00:00:00 1970
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
Subject: Re: [RFC 4/6] drm: sti: Add ASoC generic hdmi codec
	support.
Date: Tue, 19 Jan 2016 17:06:45 +0000
Message-ID: <20160119170644.GP19062@n2100.arm.linux.org.uk>
References: <1453210836-16218-1-git-send-email-arnaud.pouliquen@st.com>
 <1453210836-16218-5-git-send-email-arnaud.pouliquen@st.com>
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To: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc: Jean-Francois Moine <moinejf@free.fr>, alsa-devel@alsa-project.org, Lars-Peter Clausen <lars@metafoo.de>, Philipp Zabel <p.zabel@pengutronix.de>, David Airlie <airlied@linux.ie>, Liam Girdwood <lgirdwood@gmail.com>, Jyri Sarha <jsarha@ti.com>, Takashi Iwai <tiwai@suse.de>, Mark Brown <broonie@kernel.org>, Benjamin Gaignard <benjamin.gaignard@linaro.org>
List-Id: alsa-devel@alsa-project.org

On Tue, Jan 19, 2016 at 02:40:34PM +0100, Arnaud Pouliquen wrote:
> +	/* update N parameter */
> +	ret = hdmi_audio_compute_n_cts(params->sample_rate,
> +				       hdmi->mode.clock, &n_cts);
> +	if (ret < 0)
> +		return ret;
> +
> +	DRM_DEBUG_DRIVER("sample_frequency= %d, pix clock = %d\n",
> +			 params->sample_rate, hdmi->mode.clock);
> +	DRM_DEBUG_DRIVER("n= %d, cts = %d\n", n_cts.n, n_cts.cts);
> +
> +	hdmi_write(hdmi, n_cts.n, HDMI_AUDN);

This looks like you only make use of the N parameter, which suggests
that your hardware measures the CTS parameter itself - which means
you have the non-coherent clock case.  You'll want to refer to the
HDMI specs and use different N values from the coherent case.

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