ALSA: usb - Quirk to disable master volume control in PCM2702 (0c3cee57) · Commits · 戴 / test

Disable the master volume control in the PCM2702 chipset. The datasheet documents two independent channel volume controls, one master mute control and one master volume control. All controls are fully functional except for the master volume control, which returns USB stalls on all GET requests. Signed-off-by:

Javier Kohen <jkohen@users.sourceforge.net> Signed-off-by:

Takashi Iwai <tiwai@suse.de>

sound/usb/usbmixer.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -1071,6 +1071,15 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, unsig
		channels = (ftr[0] - 7) / csize - 1;

		master_bits = snd_usb_combine_bytes(ftr + 6, csize);
		/* master configuration quirks */
		switch (state->chip->usb_id) {
		case USB_ID(0x08bb, 0x2702):
		snd_printk(KERN_INFO
		"usbmixer: master volume quirk for PCM2702 chip\n");
		/* disable non-functional volume control */
		master_bits &= ~(1 << (USB_FEATURE_VOLUME - 1));
		break;
		}
		if (channels > 0)
		first_ch_bits = snd_usb_combine_bytes(ftr + 6 + csize, csize);
		else

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