Commit fe773b87 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: workaround for iface reset issue 



The recently introduced sample rate validation code seems causing a
problem on some devices; namely, after performing this, the bus gets
screwed and it influences even on other USB devices.
As a quick workaround, perform it only for the necessary devices;
currently MOTU devices are known to need the valid altset checks, so
filter out other devices.

Fixes: 93db51d0 ("ALSA: usb-audio: Check valid altsetting at parsing rates for UAC2/3")
Reported-by: default avatarJamie Heilman <jamie@audible.transient.net>
BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1178203
Link: https://lore.kernel.org/r/20210123155842.22652-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 23b53d44

sound/usb/format.c

+11 −0
Original line number Diff line number Diff line
@@ -466,6 +466,17 @@ static int validate_sample_rate_table_v2v3(struct snd_usb_audio *chip, 
	unsigned int nr_rates;

	int i, err;



	/* performing the rate verification may lead to unexpected USB bus

	 * behavior afterwards by some unknown reason.  Do this only for the

	 * known devices.

	 */

	switch (USB_ID_VENDOR(chip->usb_id)) {

	case 0x07fd: /* MOTU */

		break;

	default:

		return 0; /* don't perform the validation as default */

	}



	table = kcalloc(fp->nr_rates, sizeof(*table), GFP_KERNEL);

	if (!table)

		return -ENOMEM;