[Intel-gfx] [PATCH v2 1/3] ALSA: hda/hdmi: fix i915 silent stream programming flow

[Kai Vehmanen <kai.vehmanen@linux.intel.com>]

The i915 display codec may not successfully transition to
normal audio streaming mode, if the stream id is programmed
while codec is actively transmitting data. This can happen
when silent stream is enabled in KAE mode.

Fix the issue by implementing a i915 specific programming
flow, where the silent streaming is temporarily stopped,
a small delay is applied to ensure display codec becomes
idle, and then proceed with reprogramming the stream ID.

Fixes: 15175a4f2bbb ("ALSA: hda/hdmi: add keep-alive support for ADL-P and DG2")
Link: https://gitlab.freedesktop.org/drm/intel/-/issues/7353
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 sound/pci/hda/patch_hdmi.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 7a40ddfd695a..48bb23745ed3 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -2879,9 +2879,33 @@ static int i915_hsw_setup_stream(struct hda_codec *codec, hda_nid_t cvt_nid,
 				 hda_nid_t pin_nid, int dev_id, u32 stream_tag,
 				 int format)
 {
+	struct hdmi_spec *spec = codec->spec;
+	int pin_idx = pin_id_to_pin_index(codec, pin_nid, dev_id);
+	struct hdmi_spec_per_pin *per_pin;
+	int res;
+
+	if (pin_idx < 0)
+		per_pin = NULL;
+	else
+		per_pin = get_pin(spec, pin_idx);
+
 	haswell_verify_D0(codec, cvt_nid, pin_nid);
-	return hdmi_setup_stream(codec, cvt_nid, pin_nid, dev_id,
-				 stream_tag, format);
+
+	if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin && per_pin->silent_stream) {
+		silent_stream_set_kae(codec, per_pin, false);
+		/* wait for pending transfers in codec to clear */
+		usleep_range(100, 200);
+	}
+
+	res = hdmi_setup_stream(codec, cvt_nid, pin_nid, dev_id,
+				stream_tag, format);
+
+	if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin && per_pin->silent_stream) {
+		usleep_range(100, 200);
+		silent_stream_set_kae(codec, per_pin, true);
+	}
+
+	return res;
 }
 
 /* pin_cvt_fixup ops override for HSW+ and VLV+ */
-- 
2.38.1