This isn't Ubuntu/Debian specific and should be applied upstream?
On Sat, 07 Jul 2007 the mental interface of David Decotigny told:
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Hi,
Imagine you have this kind of control:
Simple mixer control 'Input Source',0 Capabilities: enum Items: 'Mic' 'Front Mic' 'Line' Item0: 'Mic'
... and you want to set it to 'Front Mic':
shell> amixer sset 'Input Source' 'Front Mic' Simple mixer control 'Input Source',0 Capabilities: enum Items: 'Mic' 'Front Mic' 'Line' Item0: 'Mic'
This does not work ! Because amixer will think that 'Front' is a modifier for 'Mic'.
Attached is a patch against alsa-utils-1.0.13-1ubuntu5 that solves this. With this patch, one can bypass the modifier parsing: one simply escapes the parameter with one or more backslash(es), and that's all:
shell> amixer sset 'Input Source' '\Front Mic' Simple mixer control 'Input Source',0 Capabilities: enum Items: 'Mic' 'Front Mic' 'Line' Item0: 'Front Mic'
What this patch also does, is that it adds correct identification of items. With the original version, given the following enumeration: foo foobar Then the parameter 'foobar' will be identified as 'foo', not 'foobar'. The patch should solve this potential problem (not tested though).
Bye, -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
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diff -ru alsa-utils-1.0.13/amixer/amixer.1 alsa-utils-1.0.13-mine/amixer/amixer.1 --- alsa-utils-1.0.13/amixer/amixer.1 2006-09-29 04:53:26.000000000 -0700 +++ alsa-utils-1.0.13-mine/amixer/amixer.1 2007-07-07 13:09:04.000000000 -0700 @@ -44,11 +44,14 @@ The parameters \fIcap, nocap, mute, unmute, toggle\fP are used to change capture (recording) and muting for the group specified.
-The optional modifiers can be put as extra parameters to specify -the stream direction or channels to apply. -The modifiers \fIplayback\fP and \fIcapture\fP specify the stream, -and the modifiers \fIfront, rear, center, woofer\fP are used to specify -channels to be changed. +The optional modifiers can be put as extra parameters to specify the +stream direction or channels to apply. The modifiers \fIplayback\fP +and \fIcapture\fP specify the stream, and the modifiers \fIfront, +rear, center, woofer\fP are used to specify channels to be changed. If +there is a confusion between the parameter and these modifiers, then +any character in the parameter may be escaped with a backslash to +disambiguate: '\Front Mic' will be understood as "parameter 'Front +Mic'", and not as "modifier 'Front' applied to 'Mic' parameter".
A simple mixer control must be specified. Only one device can be controlled at a time. diff -ru alsa-utils-1.0.13/amixer/amixer.c alsa-utils-1.0.13-mine/amixer/amixer.c --- alsa-utils-1.0.13/amixer/amixer.c 2007-07-07 13:03:39.000000000 -0700 +++ alsa-utils-1.0.13-mine/amixer/amixer.c 2007-07-07 12:59:19.000000000 -0700 @@ -1333,6 +1333,16 @@ return def; }
+/** Transform '\a\b c \de' into 'ab c de' */ +static void unescape(char * arg) +{
- char * c;
- for (c = arg ; arg && *arg ; arg ++)
- if (*arg != '\')
*(c++) = *arg;- *c = '\0';
+}
static int get_enum_item_index(snd_mixer_elem_t *elem, char **ptrp) { char *ptr = *ptrp; @@ -1347,7 +1357,7 @@ if (snd_mixer_selem_get_enum_item_name(elem, i, sizeof(name)-1, name) < 0) continue; len = strlen(name);
if (! strncmp(name, ptr, len)) {
if (!strncmp(name, ptr, len) && (ptr[len] == '\0')) { if (! ptr[len] || ptr[len] == ',' || ptr[len] == '\n') { ptr += len; *ptrp = ptr;@@ -1428,6 +1438,7 @@ dir = dir_mask(&ptr, dir); if (*ptr == '\0') continue;
unescape(ptr);
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