Commit 3753fcc2 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Optimize TEAC clock quirk 



Maris found out that the quirk for TEAC devices to work around the
clock setup is needed to apply only when the base clock is changed,
e.g. from 48000-based clocks (48000, 96000, 192000, 384000) to
44100-based clocks (44100, 88200, 176400, 352800), or vice versa,
while switching to another clock with the same base clock doesn't need
the (forcible) interface setup.

This patch implements the optimization for the TEAC clock quirk to
avoid the unnecessary interface re-setup.

Fixes: 5ce0b06a ("ALSA: usb-audio: Workaround for clock setup on TEAC devices")
Reported-by: default avatarMaris Abele <maris7abele@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220531130749.30357-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 9bfa7b36

sound/usb/clock.c

+8 −4
Original line number Diff line number Diff line
@@ -573,11 +573,15 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, 
	}



	/* FIXME - TEAC devices require the immediate interface setup */

	if (rate != prev_rate && USB_ID_VENDOR(chip->usb_id) == 0x0644) {

	if (USB_ID_VENDOR(chip->usb_id) == 0x0644) {

		bool cur_base_48k = (rate % 48000 == 0);

		bool prev_base_48k = (prev_rate % 48000 == 0);

		if (cur_base_48k != prev_base_48k) {

			usb_set_interface(chip->dev, fmt->iface, fmt->altsetting);

			if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)

				msleep(50);

		}

	}



validation:

	/* validate clock after rate change */