ALSA: hda/hdmi: fix failures at PCM open on Intel ICL and later

When HDMI PCM devices are opened in a specific order, with at least one
HDMI/DP receiver connected, ALSA PCM open fails to -EBUSY on the
connected monitor, on recent Intel platforms (ICL/JSL and newer). While
this is not a typical sequence, at least Pulseaudio does this every time
when it is started, to discover the available PCMs.

The rootcause is an invalid assumption in hdmi_add_pin(), where the
total number of converters is assumed to be known at the time the
function is called. On older Intel platforms this held true, but after
ICL/JSL, the order how pins and converters are in the subnode list as
returned by snd_hda_get_sub_nodes(), was changed. As a result,
information for some converters was not stored to per_pin->mux_nids.
And this means some pins cannot be connected to all converters, and
application instead gets -EBUSY instead at open.

The assumption that converters are always before pins in the subnode
list, is not really a valid one. Fix the problem in hdmi_parse_codec()
by introducing separate loops for discovering converters and pins.

BugLink: https://github.com/thesofproject/linux/issues/1978
BugLink: https://github.com/thesofproject/linux/issues/2216
BugLink: https://github.com/thesofproject/linux/issues/2217
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200703153818.2808592-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index e2b21ef5d7d12994be0ca64d332d0d11c24486a0..295cc5a989d5c02a9ebc78a24d0566980e765e2c 100644 (file)
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1804,33 +1804,43 @@ static int hdmi_add_cvt(struct hda_codec *codec, hda_nid_t cvt_nid)
 
 static int hdmi_parse_codec(struct hda_codec *codec)
 {
-       hda_nid_t nid;
+       hda_nid_t start_nid;
+       unsigned int caps;
        int i, nodes;
 
-       nodes = snd_hda_get_sub_nodes(codec, codec->core.afg, &nid);
-       if (!nid || nodes < 0) {
+       nodes = snd_hda_get_sub_nodes(codec, codec->core.afg, &start_nid);
+       if (!start_nid || nodes < 0) {
                codec_warn(codec, "HDMI: failed to get afg sub nodes\n");
                return -EINVAL;
        }
 
-       for (i = 0; i < nodes; i++, nid++) {
-               unsigned int caps;
-               unsigned int type;
+       /*
+        * hdmi_add_pin() assumes total amount of converters to
+        * be known, so first discover all converters
+        */
+       for (i = 0; i < nodes; i++) {
+               hda_nid_t nid = start_nid + i;
 
                caps = get_wcaps(codec, nid);
-               type = get_wcaps_type(caps);
 
                if (!(caps & AC_WCAP_DIGITAL))
                        continue;
 
-               switch (type) {
-               case AC_WID_AUD_OUT:
+               if (get_wcaps_type(caps) == AC_WID_AUD_OUT)
                        hdmi_add_cvt(codec, nid);
-                       break;
-               case AC_WID_PIN:
+       }
+
+       /* discover audio pins */
+       for (i = 0; i < nodes; i++) {
+               hda_nid_t nid = start_nid + i;
+
+               caps = get_wcaps(codec, nid);
+
+               if (!(caps & AC_WCAP_DIGITAL))
+                       continue;
+
+               if (get_wcaps_type(caps) == AC_WID_PIN)
                        hdmi_add_pin(codec, nid);
-                       break;
-               }
        }
 
        return 0;