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-rw-r--r--sound/usb/mixer.c30
-rw-r--r--sound/usb/mixer.h2
2 files changed, 26 insertions, 6 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 43d6417b811e..9149a84c716f 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -462,6 +462,16 @@ static int set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
int index, int value)
{
int err;
+ unsigned int read_only = (channel == 0) ?
+ cval->master_readonly :
+ cval->ch_readonly & (1 << (channel - 1));
+
+ if (read_only) {
+ snd_printdd(KERN_INFO "%s(): channel %d of control %d is read_only\n",
+ __func__, channel, cval->control);
+ return 0;
+ }
+
err = snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR, (cval->control << 8) | channel,
value);
if (err < 0)
@@ -958,7 +968,7 @@ static size_t append_ctl_name(struct snd_kcontrol *kctl, const char *str)
static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
unsigned int ctl_mask, int control,
struct usb_audio_term *iterm, int unitid,
- int read_only)
+ int readonly_mask)
{
struct uac_feature_unit_descriptor *desc = raw_desc;
unsigned int len = 0;
@@ -989,20 +999,25 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
cval->control = control;
cval->cmask = ctl_mask;
cval->val_type = audio_feature_info[control-1].type;
- if (ctl_mask == 0)
+ if (ctl_mask == 0) {
cval->channels = 1; /* master channel */
- else {
+ cval->master_readonly = readonly_mask;
+ } else {
int i, c = 0;
for (i = 0; i < 16; i++)
if (ctl_mask & (1 << i))
c++;
cval->channels = c;
+ cval->ch_readonly = readonly_mask;
}
/* get min/max values */
get_min_max(cval, 0);
- if (read_only)
+ /* if all channels in the mask are marked read-only, make the control
+ * read-only. set_cur_mix_value() will check the mask again and won't
+ * issue write commands to read-only channels. */
+ if (cval->channels == readonly_mask)
kctl = snd_ctl_new1(&usb_feature_unit_ctl_ro, cval);
else
kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
@@ -1195,9 +1210,12 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
}
}
- /* FIXME: the whole unit is read-only if any of the channels is marked read-only */
+ /* NOTE: build_feature_ctl() will mark the control read-only if all channels
+ * are marked read-only in the descriptors. Otherwise, the control will be
+ * reported as writeable, but the driver will not actually issue a write
+ * command for read-only channels */
if (ch_bits & 1) /* the first channel must be set (for ease of programming) */
- build_feature_ctl(state, _ftr, ch_bits, i, &iterm, unitid, !!ch_read_only);
+ build_feature_ctl(state, _ftr, ch_bits, i, &iterm, unitid, ch_read_only);
if (uac2_control_is_readable(master_bits, i))
build_feature_ctl(state, _ftr, 0, i, &iterm, unitid,
!uac2_control_is_writeable(master_bits, i));
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index 130123854a6c..a7cf1007fbb0 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -34,6 +34,8 @@ struct usb_mixer_elem_info {
unsigned int id;
unsigned int control; /* CS or ICN (high byte) */
unsigned int cmask; /* channel mask bitmap: 0 = master */
+ unsigned int ch_readonly;
+ unsigned int master_readonly;
int channels;
int val_type;
int min, max, res;