[alsa-devel] [PATCH] ALSA: hda - hdmi: Disallow unsupported 2ch remapping on NVIDIA codecs

[Anssi Hannula]

NVIDIA HDMI codecs do not seem to follow the Audio Sample Packet (ASP)
channel mapping (as set by verb F32h per HDA specification 7.3.3.41)
when playing back 2-channel audio (CEA CA 0x00).

Basically this means that specifying swapped channels for stereo audio
(FR,FL) does not take effect, and e.g. this command plays back on the
wrong channel:
speaker-test -c2 -Dhdmi:CARD=NVidia,DEV=0 -m FR,FL -s1

Multichannel audio is not affected.

This issue has been confirmed to exist on codec 0x10de0015 by me and on
0x10de0040 by Juho Teperi.

Disable 2ch FL/FR channel swapping on all NVIDIA HDMI codecs that use
the standard HDA channel mapping system. Since this is a very minor
functionality loss, we err on the side of disabling it for newer codecs
as well until any future testing confirms that this issue has been
fixed.

Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
Helped-by: Juho Teperi <juho.teperi at iki.fi>
Cc: Aaron Plattner <aplattner at nvidia.com>
---
 sound/pci/hda/patch_hdmi.c | 86 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 63 insertions(+), 23 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index d61cc2ab52af..c3e3537b3196 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -2787,6 +2787,46 @@ static int patch_nvhdmi_8ch_7x(struct hda_codec *codec)
 }
 
 /*
+ * NVIDIA codecs ignore ASP mapping for 2ch - confirmed on:
+ * - 0x10de0015
+ * - 0x10de0040
+ */
+static int nvhdmi_chmap_cea_alloc_validate_get_type(struct cea_channel_speaker_allocation *cap,
+						    int channels)
+{
+	if (cap->ca_index == 0x00 && channels == 2)
+		return SNDRV_CTL_TLVT_CHMAP_FIXED;
+
+	return hdmi_chmap_cea_alloc_validate_get_type(cap, channels);
+}
+
+static int nvhdmi_chmap_validate(int ca, int chs, unsigned char *map)
+{
+	if (ca == 0x00 && (map[0] != SNDRV_CHMAP_FL || map[1] != SNDRV_CHMAP_FR))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int patch_nvhdmi(struct hda_codec *codec)
+{
+	struct hdmi_spec *spec;
+	int err;
+
+	err = patch_generic_hdmi(codec);
+	if (err)
+		return err;
+
+	spec = codec->spec;
+
+	spec->ops.chmap_cea_alloc_validate_get_type =
+		nvhdmi_chmap_cea_alloc_validate_get_type;
+	spec->ops.chmap_validate = nvhdmi_chmap_validate;
+
+	return 0;
+}
+
+/*
  * ATI/AMD-specific implementations
  */
 
@@ -3167,30 +3207,30 @@ static const struct hda_codec_preset snd_hda_preset_hdmi[] = {
 { .id = 0x10de0005, .name = "MCP77/78 HDMI",	.patch = patch_nvhdmi_8ch_7x },
 { .id = 0x10de0006, .name = "MCP77/78 HDMI",	.patch = patch_nvhdmi_8ch_7x },
 { .id = 0x10de0007, .name = "MCP79/7A HDMI",	.patch = patch_nvhdmi_8ch_7x },
-{ .id = 0x10de000a, .name = "GPU 0a HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de000b, .name = "GPU 0b HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de000c, .name = "MCP89 HDMI",	.patch = patch_generic_hdmi },
-{ .id = 0x10de000d, .name = "GPU 0d HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0010, .name = "GPU 10 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0011, .name = "GPU 11 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0012, .name = "GPU 12 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0013, .name = "GPU 13 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0014, .name = "GPU 14 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0015, .name = "GPU 15 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0016, .name = "GPU 16 HDMI/DP",	.patch = patch_generic_hdmi },
+{ .id = 0x10de000a, .name = "GPU 0a HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de000b, .name = "GPU 0b HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de000c, .name = "MCP89 HDMI",	.patch = patch_nvhdmi },
+{ .id = 0x10de000d, .name = "GPU 0d HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0010, .name = "GPU 10 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0011, .name = "GPU 11 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0012, .name = "GPU 12 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0013, .name = "GPU 13 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0014, .name = "GPU 14 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0015, .name = "GPU 15 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0016, .name = "GPU 16 HDMI/DP",	.patch = patch_nvhdmi },
 /* 17 is known to be absent */
-{ .id = 0x10de0018, .name = "GPU 18 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0019, .name = "GPU 19 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de001a, .name = "GPU 1a HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de001b, .name = "GPU 1b HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de001c, .name = "GPU 1c HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0040, .name = "GPU 40 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0041, .name = "GPU 41 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0042, .name = "GPU 42 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0043, .name = "GPU 43 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0044, .name = "GPU 44 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0051, .name = "GPU 51 HDMI/DP",	.patch = patch_generic_hdmi },
-{ .id = 0x10de0060, .name = "GPU 60 HDMI/DP",	.patch = patch_generic_hdmi },
+{ .id = 0x10de0018, .name = "GPU 18 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0019, .name = "GPU 19 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de001a, .name = "GPU 1a HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de001b, .name = "GPU 1b HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de001c, .name = "GPU 1c HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0040, .name = "GPU 40 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0041, .name = "GPU 41 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0042, .name = "GPU 42 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0043, .name = "GPU 43 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0044, .name = "GPU 44 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0051, .name = "GPU 51 HDMI/DP",	.patch = patch_nvhdmi },
+{ .id = 0x10de0060, .name = "GPU 60 HDMI/DP",	.patch = patch_nvhdmi },
 { .id = 0x10de0067, .name = "MCP67 HDMI",	.patch = patch_nvhdmi_2ch },
 { .id = 0x10de8001, .name = "MCP73 HDMI",	.patch = patch_nvhdmi_2ch },
 { .id = 0x11069f80, .name = "VX900 HDMI/DP",	.patch = patch_via_hdmi },
-- 
1.8.1.5