[PATCH AUTOSEL 4.9 07/10] ALSA: hda/hdmi: fix failures at PCM open on Intel ICL and later

Sasha Levin
2020-07-14T14:41:40Z

From: Kai Vehmanen <kai.vehmanen@linux.intel.com>

[ Upstream commit 56275036d8185f92eceac7479d48b858ee3dab84 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/pci/hda/patch_hdmi.c | 36 +++++++++++++++++++++++-------------
1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 2def4ad579ccf..f7bd91b713e83 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1655,33 +1655,43 @@ 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;
--
2.25.1