[alsa-devel] parameter for pulse device?

[frederik at ofb.net]

Dear Takashi,

I tested your patch, after commenting some lines in my ~/.asoundrc, and I can confirm that it works. I can now specify a pulse device to 'ecasound':

    ecasound -o alsa,pulse:music -i song.wav

and when I do it with no "DEVICE" argument, then it outputs to the sink defined by "pacmd set-default-sink":

    ecasound -o alsa,pulse -i song.wav

I guess this only exercises one of the cases in your patch where the empty string is recognized as NULL:

+			} else if (!*device) {
+				device = NULL;

Let me know if you want me to do more testing, and apologies for the long delay in my reply.

Thanks,

Frederick


On Fri, Sep 20, 2019 at 09:44:19AM +0200, Takashi Iwai wrote:
>On Fri, 20 Sep 2019 09:35:59 +0200,
>Tanu Kaskinen wrote:
>>
>> On Thu, 2019-09-19 at 14:12 -0700, frederik at ofb.net wrote:
>> > Thank you for the tips.
>> >
>> > I don't know if my input is still needed, but I figured out from
>> > looking at some of the syntax you linked to that I can put this in
>> > ~/.asoundrc and it does the job (this is what I had had in mind when
>> > I asked about "magic with macros", it is somewhat advanced for me):
>> >
>> >     pcm.!pulse {
>> >         @args [ DEV ]
>> >         @args.DEV {
>> >             type string
>> >             default "default"
>> >         }
>> >         type pulse;
>> >         device $DEV
>> >     }
>> >
>> > Now I can set up a filter like this:
>> >
>> >     ecasound -i alsa,pulse:mic -o alsa,pulse:monitor
>> >
>> > Is something like this going into the alsa-plugins repo?
>>
>> I'm sure something like this will be accepted if you submit a patch. I
>> got the impression that Takashi isn't willing to write the patch
>> himself, and nor am I, so you're in the best position to make this
>> happen.
>
>I have a test patch but had no chance to test the stuff at all
>currently as I am (and will be for the next few weeks) traveling.
>
>> Note that
>>
>>             default "default"
>>
>> doesn't do the intended thing with the current pcm_pulse.c code. With
>> the current code the plugin will request PulseAudio to use a device
>> named "default", which most likely won't exist and playback or
>> recording will fail. The plugin code needs to pass NULL as the device
>> name to pa_stream_connect_playback() and pa_stream_connect_record()
>> when it detects that the default device is requested, so you'll need to
>> modify pcm_pulse.c in order to make this work. Instead of "default" as
>> the special string in the configuration, I suggested using "".
>
>Below is the totally untested patch (even not build-tested!)
>If anyone interested, feel free to cook it.
>
>
>thanks,
>
>Takashi
>
>---
>diff --git a/pulse/50-pulseaudio.conf b/pulse/50-pulseaudio.conf
>index 62da207af9ca..916258d942af 100644
>--- a/pulse/50-pulseaudio.conf
>+++ b/pulse/50-pulseaudio.conf
>@@ -1,7 +1,13 @@
> # Add a specific named PulseAudio pcm and ctl (typically useful for testing)
>
> pcm.pulse {
>+	@args [ DEVICE ]
>+	@args.DEVICE {
>+		type string
>+		default ""
>+	}
> 	type pulse
>+	device $DEVICE
> 	hint {
> 		show {
> 			@func refer
>diff --git a/pulse/ctl_pulse.c b/pulse/ctl_pulse.c
>index fbb6eae2ec76..9b820fd04b15 100644
>--- a/pulse/ctl_pulse.c
>+++ b/pulse/ctl_pulse.c
>@@ -664,6 +664,8 @@ SND_CTL_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &server) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*server) {
>+				server = NULL;
> 			}
> 			continue;
> 		}
>@@ -671,6 +673,8 @@ SND_CTL_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &device) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*device) {
>+				device = NULL;
> 			}
> 			continue;
> 		}
>@@ -678,6 +682,8 @@ SND_CTL_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &source) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*source) {
>+				source = NULL;
> 			}
> 			continue;
> 		}
>@@ -685,6 +691,8 @@ SND_CTL_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &sink) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*sink) {
>+				sink = NULL;
> 			}
> 			continue;
> 		}
>diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
>index 283174357e8b..869c9b674c6b 100644
>--- a/pulse/pcm_pulse.c
>+++ b/pulse/pcm_pulse.c
>@@ -1069,6 +1069,8 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &server) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*server) {
>+				server = NULL;
> 			}
> 			continue;
> 		}
>@@ -1076,6 +1078,8 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &device) < 0) {
> 				SNDERR("Invalid type for %s", id);
> 				return -EINVAL;
>+			} else if (!*device) {
>+				device = NULL;
> 			}
> 			continue;
> 		}
>@@ -1091,6 +1095,8 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
> 			if (snd_config_get_string(n, &fallback_name) < 0) {
> 				SNDERR("Invalid value for %s", id);
> 				return -EINVAL;
>+			} else if (!*fallback_name) {
>+				fallback_name = NULL;
> 			}
> 			continue;
> 		}
>