Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a6a33259 authored by Daniel Mack's avatar Daniel Mack Committed by Takashi Iwai
Browse files

ALSA: usb-audio: support partially write-protected UAC2 controls 



So far, UAC2 controls are marked read-only if any of the channels are
marked read-only in the descriptors. Change this behaviour and

 - mark them writeable unless all channels are read-only
 - store the read-only mask in usb_mixer_elem_info and
 - check the mask again in set_cur_mix_value(), and bail out for
   write-protected channels.

Signed-off-by: default avatarDaniel Mack <daniel@caiaq.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent dcbe7bcf

sound/usb/mixer.c

+24 −6
Original line number Diff line number Diff line
@@ -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));

sound/usb/mixer.h

+2 −0
Original line number Diff line number Diff line
@@ -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;