[alsa-devel] [PATCH v3 01/10] ALSA: hda/hdmi - implement mst_no_extra_pcms flag

[Kai Vehmanen]

When mst_no_extra_pcms flag is set, the codec should not
use backup PCMs to handle DP-MST scenarios. Instead a simple
1:1 mapping is assumed between PCMs and converters.

Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
---
 include/sound/hda_codec.h  |  1 +
 sound/pci/hda/patch_hdmi.c | 19 ++++++++++++++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h
index 9a0393cf024c..ac18f428eda6 100644
--- a/include/sound/hda_codec.h
+++ b/include/sound/hda_codec.h
@@ -254,6 +254,7 @@ struct hda_codec {
 	unsigned int force_pin_prefix:1; /* Add location prefix */
 	unsigned int link_down_at_suspend:1; /* link down at runtime suspend */
 	unsigned int relaxed_resume:1;	/* don't resume forcibly for jack */
+	unsigned int mst_no_extra_pcms:1; /* no backup PCMs for DP-MST */
 
 #ifdef CONFIG_PM
 	unsigned long power_on_acct;
diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index bca5de78e9ad..59aaee4a40fd 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -2072,15 +2072,24 @@ static bool is_hdmi_pcm_attached(struct hdac_device *hdac, int pcm_idx)
 static int generic_hdmi_build_pcms(struct hda_codec *codec)
 {
 	struct hdmi_spec *spec = codec->spec;
-	int idx;
+	int idx, pcm_num;
 
 	/*
 	 * for non-mst mode, pcm number is the same as before
-	 * for DP MST mode, pcm number is (nid number + dev_num - 1)
-	 *  dev_num is the device entry number in a pin
-	 *
+	 * for DP MST mode without extra PCM, pcm number is same
+	 * for DP MST mode with extra PCMs, pcm number is
+	 *  (nid number + dev_num - 1)
+	 * dev_num is the device entry number in a pin
 	 */
-	for (idx = 0; idx < spec->num_nids + spec->dev_num - 1; idx++) {
+
+	if (codec->mst_no_extra_pcms)
+		pcm_num = spec->num_nids;
+	else
+		pcm_num = spec->num_nids + spec->dev_num - 1;
+
+	codec_dbg(codec, "hdmi: pcm_num set to %d\n", pcm_num);
+
+	for (idx = 0; idx < pcm_num; idx++) {
 		struct hda_pcm *info;
 		struct hda_pcm_stream *pstr;
 
-- 
2.17.1