diff options
| -rw-r--r-- | sound/usb/mixer.c | 30 | ||||
| -rw-r--r-- | sound/usb/mixer.h | 2 |
2 files changed, 26 insertions, 6 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 43d6417b811..9149a84c716 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 130123854a6..a7cf1007fbb 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; |