Re: human-readable audio device descriptions
On Wed, Jul 07, 2021 at 03:13:37PM +0100, Edd Barrett wrote:
> Hi,
>
> This diff is an attempt to make identifying audio devices easier by
> giving each device a human-readable description that can be read from
> userspace (and without scraping dmesg).
>
> This is implemented on a per-audio-device basis using a new `descr`
> interface to `audio_hw_if`. For now I've only implemented this on:
>
> - azalia(4), which uses the codec info, e.g. `Realtek ALC1150`
>
> - uaudio(4), which uses the USB vendor and model info, e.g.
>`Logitech HD Pro Webcam C920`.
>
> For drivers, which currently don't implement this interface, the
> description string defaults to the audio device node name, e.g.
> `uaudio2`.
>
> The string is exposed to userspace via the AUDIO_GETDEV ioctl(2). I've
> reclaimed the space currently occupied by the (unused) `version` and
> `config` fields in `audio_device_t` and used it for a new `descr` field.
> Thus the size of `audio_device_t` remains the same for now.
>
> I've also made audioctl(8) display the description string, e.g.:
> ```
> # audioctl
> name=azalia1
> descr=Realtek ALC1150
> ...
> # audioctl -f /dev/audioctl1
> name=uaudio0
> descr=SteelSeries SteelSeries Arctis
> ...
> ```
>
> I'm hoping that later we can have sndiod read these strings and expose
> them to its clients. For example, I'd like for sndioctl(1) to allow
> choosing a device based on the device description string (instead of the
> sndio device index), and for xfce4-mixer to allow choosing a device via
> its description in the GUI using a drop-down box.
>
> Diff follows.
>
[...]
> @@ -4019,6 +4021,37 @@ azalia_set_nblks(void *v, int mode,
> nblks = HDA_BDL_MAX;
>
> return nblks;
> +}
> +
> +void
> +azalia_descr(void *arg, char *descr, size_t len)
> +{
> + azalia_t *az = arg;
> + codec_t *codec;
> + const char *vendor;
> + char buf[MAX_AUDIO_DESCR_LEN];
> + int i;
> +
> + *descr = '\0';
> + for (i = 0; i < az->ncodecs; i++) {
azalia(4) fetches all codecs, but uses (and supports) only one of
them. You should copy the name of the one in use, ie
az->codecs[az->codecno].
> + codec = >codecs[i];
> + /* adapted from azalia_print_codec() */
> + if (codec->name == NULL) {
> + vendor = pci_findvendor(codec->vid >> 16);
> + if (vendor == NULL)
> + snprintf(buf, MAX_AUDIO_DESCR_LEN,
> + "0x%04x/0x%04x", codec->vid >> 16,
> + codec->vid & 0x);
> + else
> + snprintf(buf, MAX_AUDIO_DESCR_LEN, "%s/0x%04x",
> + vendor, codec->vid & 0x);
> + } else
> + snprintf(buf, MAX_AUDIO_DESCR_LEN, "%s", codec->name);
> +
> + if (i > 0)
> + strlcat(descr, ", ", len);
> + strlcat(descr, buf, len);
> + }
> }
>
> int
> Index: sys/sys/audioio.h
> ===
> RCS file: /cvs/src/sys/sys/audioio.h,v
> retrieving revision 1.27
> diff -u -p -r1.27 audioio.h
> --- sys/sys/audioio.h 14 Sep 2016 06:12:20 - 1.27
> +++ sys/sys/audioio.h 7 Jul 2021 10:23:09 -
> @@ -76,10 +76,10 @@ struct audio_status {
> * audio devices.
> */
> #define MAX_AUDIO_DEV_LEN16
> +#define MAX_AUDIO_DESCR_LEN 32
> typedef struct audio_device {
> char name[MAX_AUDIO_DEV_LEN];
> - char version[MAX_AUDIO_DEV_LEN];
> - char config[MAX_AUDIO_DEV_LEN];
> + char descr[MAX_AUDIO_DESCR_LEN]; /* device description string */
> } audio_device_t;
>
The intent of the "name" field was to be human-readable as well. You
could just replace it. There's no benefit in having two fields for the
same thing.
Re: human-readable audio device descriptions
On Wed, Jul 07, 2021 at 08:25:16AM -0600, Theo de Raadt wrote: > > This diff is an attempt to make identifying audio devices easier by > > giving each device a human-readable description that can be read from > > userspace (and without scraping dmesg). > > But why does anyone want that? > > Isn't everyone served best when there is a public portable interface, > and all the back-ends must try to work the same? Exactly. The long-term aim is to expose this information to programs through sndiod with a stable libsndio interface, which in turn would ease switching between audio devices. This diff is the first step; IMO, it's not necessary until we get the whole chain, but it doesn't hurt either; it improves audioctl(8) output, which is a dignostics-only tool.
Re: human-readable audio device descriptions
> This diff is an attempt to make identifying audio devices easier by > giving each device a human-readable description that can be read from > userspace (and without scraping dmesg). But why does anyone want that? Isn't everyone served best when there is a public portable interface, and all the back-ends must try to work the same?
human-readable audio device descriptions
Hi,
This diff is an attempt to make identifying audio devices easier by
giving each device a human-readable description that can be read from
userspace (and without scraping dmesg).
This is implemented on a per-audio-device basis using a new `descr`
interface to `audio_hw_if`. For now I've only implemented this on:
- azalia(4), which uses the codec info, e.g. `Realtek ALC1150`
- uaudio(4), which uses the USB vendor and model info, e.g.
`Logitech HD Pro Webcam C920`.
For drivers, which currently don't implement this interface, the
description string defaults to the audio device node name, e.g.
`uaudio2`.
The string is exposed to userspace via the AUDIO_GETDEV ioctl(2). I've
reclaimed the space currently occupied by the (unused) `version` and
`config` fields in `audio_device_t` and used it for a new `descr` field.
Thus the size of `audio_device_t` remains the same for now.
I've also made audioctl(8) display the description string, e.g.:
```
# audioctl
name=azalia1
descr=Realtek ALC1150
...
# audioctl -f /dev/audioctl1
name=uaudio0
descr=SteelSeries SteelSeries Arctis
...
```
I'm hoping that later we can have sndiod read these strings and expose
them to its clients. For example, I'd like for sndioctl(1) to allow
choosing a device based on the device description string (instead of the
sndio device index), and for xfce4-mixer to allow choosing a device via
its description in the GUI using a drop-down box.
Diff follows.
Index: sys/dev/audio.c
===
RCS file: /cvs/src/sys/dev/audio.c,v
retrieving revision 1.193
diff -u -p -r1.193 audio.c
--- sys/dev/audio.c 16 May 2021 15:12:37 - 1.193
+++ sys/dev/audio.c 7 Jul 2021 10:21:25 -
@@ -1791,6 +1791,11 @@ audio_getdev(struct audio_softc *sc, str
if (sc->dev.dv_parent == NULL)
return EIO;
strlcpy(adev->name, sc->dev.dv_parent->dv_xname, MAX_AUDIO_DEV_LEN);
+ if (sc->ops->descr != NULL)
+ sc->ops->descr(sc->arg, adev->descr, MAX_AUDIO_DESCR_LEN);
+ else
+ strlcpy(adev->descr, sc->dev.dv_parent->dv_xname,
+ MAX_AUDIO_DESCR_LEN);
return 0;
}
Index: sys/dev/audio_if.h
===
RCS file: /cvs/src/sys/dev/audio_if.h,v
retrieving revision 1.36
diff -u -p -r1.36 audio_if.h
--- sys/dev/audio_if.h 5 Sep 2019 05:33:57 - 1.36
+++ sys/dev/audio_if.h 2 Jul 2021 19:15:53 -
@@ -137,6 +137,8 @@ struct audio_hw_if {
struct audio_params *, struct audio_params *, unsigned int);
unsigned int (*set_nblks)(void *, int,
struct audio_params *, unsigned int, unsigned int);
+
+ void(*descr)(void*, char *, size_t); /* the device's description */
};
struct audio_attach_args {
Index: sys/dev/pci/azalia.c
===
RCS file: /cvs/src/sys/dev/pci/azalia.c,v
retrieving revision 1.263
diff -u -p -r1.263 azalia.c
--- sys/dev/pci/azalia.c11 Jun 2021 15:46:09 - 1.263
+++ sys/dev/pci/azalia.c2 Jul 2021 19:15:53 -
@@ -256,6 +256,7 @@ unsigned int azalia_set_blksz(void *, in
struct audio_params *, struct audio_params *, unsigned int);
unsigned int azalia_set_nblks(void *, int,
struct audio_params *, unsigned int, unsigned int);
+void azalia_descr(void *, char *, size_t);
intazalia_halt_output(void *);
intazalia_halt_input(void *);
intazalia_set_port(void *, mixer_ctrl_t *);
@@ -315,7 +316,8 @@ struct audio_hw_if azalia_hw_if = {
NULL, /* copy_output */
NULL, /* underrun */
azalia_set_blksz,
- azalia_set_nblks
+ azalia_set_nblks,
+ azalia_descr/* descr */
};
static const char *pin_devices[16] = {
@@ -4019,6 +4021,37 @@ azalia_set_nblks(void *v, int mode,
nblks = HDA_BDL_MAX;
return nblks;
+}
+
+void
+azalia_descr(void *arg, char *descr, size_t len)
+{
+ azalia_t *az = arg;
+ codec_t *codec;
+ const char *vendor;
+ char buf[MAX_AUDIO_DESCR_LEN];
+ int i;
+
+ *descr = '\0';
+ for (i = 0; i < az->ncodecs; i++) {
+ codec = >codecs[i];
+ /* adapted from azalia_print_codec() */
+ if (codec->name == NULL) {
+ vendor = pci_findvendor(codec->vid >> 16);
+ if (vendor == NULL)
+ snprintf(buf, MAX_AUDIO_DESCR_LEN,
+ "0x%04x/0x%04x", codec->vid >> 16,
+ codec->vid & 0x);
+ else
+ snprintf(buf, MAX_AUDIO_DESCR_LEN, "%s/0x%04x",
+ vendor, codec->vid & 0x);
+ } else
+
