ALSA: hda - hdmi: Disable ramp-up/down for non-PCM on AMD codecs

Recent AMD HDMI codecs (revision ID 3 and later, 0x100300 as reported by
procfs codec#0) have a configurable ramp-up/down functionality.

The documentation ( http://www.x.org/docs/AMD/AMD_HDA_verbs_v2.pdf )
specifies that 180 ("180/256 =~ 0.7") is recommended for PCM and 0 for
non-PCM.

Apply the recommended values according to provided S/PDIF AES0 settings
since ramp-up/down does not make sense for non-PCM.

v2: adapted to hdmi_ops infrastructure

* More note from Anssi:
actually, re-reading mails reveals that Olivier didn't find the
expected difference with this setting, except for "maybe slightly
slower startup with AES0=6" (i.e. value 0, which is unexpected).

So maybe
a) it makes too unnoticiable a difference, or
b) only affects certain hardware (card and/or sink), or
c) ramp-up/down is only triggered with the MUTE bit of
   ATI_VERB_SET_MULTICHANNEL_xx which is also rev3+ specific,
   but is not presently used by the driver,
or something else.

So there's a significant chance setting ramp rate is useless for us ATM,
but probably does not do actual harm either.
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Tested-by: Olivier Langlois <olivier@trillion01.com> # v1
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_hdmi.c

@@ -2818,6 +2818,10 @@ static int patch_nvhdmi_8ch_7x(struct hda_codec *codec)
 #define ATI_VERB_GET_MULTICHANNEL_7	0xf88
 #define ATI_VERB_GET_MULTICHANNEL_MODE	0xf89
 
+/* AMD specific HDA cvt verbs */
+#define ATI_VERB_SET_RAMP_RATE		0x770
+#define ATI_VERB_GET_RAMP_RATE		0xf70
+
 #define ATI_OUT_ENABLE 0x1
 
 #define ATI_MULTICHANNEL_MODE_PAIRED	0
@@ -3049,6 +3053,23 @@ static int atihdmi_pin_hbr_setup(struct hda_codec *codec, hda_nid_t pin_nid,
 	return 0;
 }
 
+static int atihdmi_setup_stream(struct hda_codec *codec, hda_nid_t cvt_nid,
+				hda_nid_t pin_nid, u32 stream_tag, int format)
+{
+
+	if (is_amdhdmi_rev3_or_later(codec)) {
+		int ramp_rate = 180; /* default as per AMD spec */
+		/* disable ramp-up/down for non-pcm as per AMD spec */
+		if (format & AC_FMT_TYPE_NON_PCM)
+			ramp_rate = 0;
+
+		snd_hda_codec_write(codec, cvt_nid, 0, ATI_VERB_SET_RAMP_RATE, ramp_rate);
+	}
+
+	return hdmi_setup_stream(codec, cvt_nid, pin_nid, stream_tag, format);
+}
+
+
 static int atihdmi_init(struct hda_codec *codec)
 {
 	struct hdmi_spec *spec = codec->spec;
@@ -3095,6 +3116,7 @@ static int patch_atihdmi(struct hda_codec *codec)
 	spec->ops.pin_set_slot_channel = atihdmi_pin_set_slot_channel;
 	spec->ops.pin_setup_infoframe = atihdmi_pin_setup_infoframe;
 	spec->ops.pin_hbr_setup = atihdmi_pin_hbr_setup;
+	spec->ops.setup_stream = atihdmi_setup_stream;
 
 	if (!has_amd_full_remap_support(codec)) {
 		/* override to ATI/AMD-specific versions with pairwise mapping */