[alsa-devel] 2 speakers are assigned to the same DAC, this can't support 4.0/2.1 channles

[Takashi Iwai]

At Tue, 09 Jun 2015 17:38:33 +0800,
hwang4 wrote:
> 
> I am trying to enable the subwoofer speaker on a HP laptop, on this
> machine, there are two speakers and one headphone, but the BIOS verb
> only enabled one speaker(nid 0xd) and one headphone(nid 0xb), I need
> to use quirk in the kernel driver to configure the second speaker
> (subwoofer speaker, nid 0x10). Under current alsa driver, the
> headphone will be assigned a dac (nid 0x13) and the 2 speakers will
> be assigned a dac (nid 0x14), this assignment is not good since 2
> speakers share the same dac, this means 2 speakers can't work
> at the same time to support 4.0/2.1 channels.
> 
> On another Dell machine with realtek codec, there are also 2 speakers,
> 1 headphone and 2 dacs, on this machine, 1 speaker and 1 headphone are 
> assigned
> 1 dac, and the other speaker is assigned another dac, so there is no
> problem for this machine to support 4.0/2.1 channels.
> 
> Through debugging, I found on Dell machine, the speaker nid only has
> one connection to dac (hardwired), so when driver assign dac to it, the
> map_single() can successfully assign the each dac to the 2 speakers 
> respectively.
> But on that HP machine, the speaker has multiple connections for dac, the
> map_single() can't work for this machine.
> 
> 
> The alsa-info.txt for that HP machine is at 
> http://pastebin.ubuntu.com/11667947/
> The alsa-info.txt for that Dell machine is at 
> http://pastebin.ubuntu.com/11667982/
> 
> To fix this problem, I can use the quirk in the driver to make the 
> speaker have
> only one connection for dac or do some change in the hda_generic.c like 
> below, in
> your opinion, which one is better or probably you have a different idea 
> to fix this problem?
> 
> diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
> index ac0db16..8194ff1 100644
> --- a/sound/pci/hda/hda_generic.c
> +++ b/sound/pci/hda/hda_generic.c
> @@ -1363,6 +1363,7 @@ static int try_assign_dacs(struct hda_codec 
> *codec, int num_outs,
>                                  dac = try_dac(codec, 
> get_primary_out(codec, i), pin);
>                          if (!dac)
>                                  dac = try_dac(codec, dacs[0], pin);
>                          if (!dac)
>                                  dac = try_dac(codec, 
> get_primary_out(codec, i), pin);
>                          if (dac) {
> @@ -1762,6 +1763,12 @@ static int fill_and_eval_dacs(struct hda_codec 
> *codec,
>                  if (err < 0)
>                          return err;
>                  badness += err;
> +               /* if there are 2 speakers and both of them are assigned 
> to the same dac,
> +                  we need to increase the badness for this situation, 
> because in this situation
> +                  the 2 speakers can't work together to support 4.0/2.1 
> channels */
> +               if (cfg->speaker_outs == 2 && err < 
> spec->extra_out_badness->no_dac &&
> +                   spec->multiout.extra_out_nid[1] == 0)
> +                       badness += spec->extra_out_badness->no_dac;

This doesn't look like the correct place to add badness for the
missing surround speaker.  This function is called for each path, so
it's evaluated not only for speakers.

A cleaner way would be to prepare a different badness table for the
speaker, and increase the value for shared_surr.  An untested patch is
below.


Takashi

---
diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index ac0db1679f09..ee03fb884426 100644
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -1292,6 +1292,15 @@ const struct badness_table hda_extra_out_badness = {
 };
 EXPORT_SYMBOL_GPL(hda_extra_out_badness);
 
+static const struct badness_table hda_speaker_out_badness = {
+	.no_primary_dac = BAD_NO_DAC,
+	.no_dac = BAD_NO_DAC,
+	.shared_primary = BAD_NO_EXTRA_DAC,
+	.shared_surr = BAD_NO_EXTRA_DAC,
+	.shared_clfe = BAD_SHARED_EXTRA_SURROUND,
+	.shared_surr_main = BAD_NO_EXTRA_SURR_DAC,
+};
+
 /* get the DAC of the primary output corresponding to the given array index */
 static hda_nid_t get_primary_out(struct hda_codec *codec, int idx)
 {
@@ -1758,7 +1767,7 @@ static int fill_and_eval_dacs(struct hda_codec *codec,
 				      cfg->speaker_pins,
 				      spec->multiout.extra_out_nid,
 				      spec->speaker_paths,
-				      spec->extra_out_badness);
+				      spec->speaker_out_badness);
 		if (err < 0)
 			return err;
 		badness += err;
@@ -4789,6 +4798,8 @@ int snd_hda_gen_parse_auto_config(struct hda_codec *codec,
 		spec->main_out_badness = &hda_main_out_badness;
 	if (!spec->extra_out_badness)
 		spec->extra_out_badness = &hda_extra_out_badness;
+	if (!spec->speaker_out_badness)
+		spec->speaker_out_badness = &hda_speaker_out_badness;
 
 	fill_all_dac_nids(codec);
 
diff --git a/sound/pci/hda/hda_generic.h b/sound/pci/hda/hda_generic.h
index 56e4139b9032..1f868de1aec4 100644
--- a/sound/pci/hda/hda_generic.h
+++ b/sound/pci/hda/hda_generic.h
@@ -246,6 +246,7 @@ struct hda_gen_spec {
 	/* badness tables for output path evaluations */
 	const struct badness_table *main_out_badness;
 	const struct badness_table *extra_out_badness;
+	const struct badness_table *speaker_out_badness;
 
 	/* preferred pin/DAC pairs; an array of paired NIDs */
 	const hda_nid_t *preferred_dacs;
diff --git a/sound/pci/hda/patch_via.c b/sound/pci/hda/patch_via.c
index 0521be8d46a8..9e9d0456dab7 100644
--- a/sound/pci/hda/patch_via.c
+++ b/sound/pci/hda/patch_via.c
@@ -579,6 +579,7 @@ static int via_parse_auto_config(struct hda_codec *codec)
 
 	spec->gen.main_out_badness = &via_main_out_badness;
 	spec->gen.extra_out_badness = &via_extra_out_badness;
+	spec->gen.speaker_out_badness = &via_extra_out_badness;
 
 	err = snd_hda_parse_pin_defcfg(codec, &spec->gen.autocfg, NULL, 0);
 	if (err < 0)