[alsa-devel] [PATCH] ALSA: hda - skip depop delay before D3 for Haswell and Valleyview2 display codec

[mengdong.lin at intel.com]

From: Mengdong Lin <mengdong.lin at intel.com>

This patch skips the default depop delay before D3 for Haswell (10 ms) and
Valleyview2 (100 ms) display codec, to reduce codec suspend time.

The analog part of display audio is implemented in the external display. Some
displays have weak pop noise while others not when suspending, no matter there
is the default delay or not.

Signed-off-by: Mengdong Lin <mengdong.lin at intel.com>

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 2306645..e14359a 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -2022,6 +2022,10 @@ static int patch_generic_hdmi(struct hda_codec *codec)
 		intel_haswell_fixup_enable_dp12(codec);
 	}
 
+	if (is_haswell(codec) || is_valleyview(codec)) {
+		codec->depop_delay = 0;
+	}
+
 	if (hdmi_parse_codec(codec) < 0) {
 		codec->spec = NULL;
 		kfree(spec);
-- 
1.8.1.2