[PATCH] ALSA: usb-audio: don't try to get Benchmark DAC1 sample rate

From: Eric Wong <normalperson@yhbt.net>
To: Takashi Iwai <tiwai@suse.de>, Joe Turner <joe@oampo.co.uk>
Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	Eric Wong <normalperson@yhbt.net>
Subject: [PATCH] ALSA: usb-audio: don't try to get Benchmark DAC1 sample rate
Date: Tue, 31 Mar 2015 07:34:05 +0000	[thread overview]
Message-ID: <20150331073405.GA5912@dcvr.yhbt.net> (raw)

Adding this quirk allows us to avoid the noisy
"cannot get freq at ep 0x1" message in dmesg output every time
playback starts.

This ought to affect other Benchmark DAC1 variations using the same
"Microchip Technology, Inc." chip as well, but I have only tested
with the "Pre" variant.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Cc: Joe Turner <joe@oampo.co.uk>
Cc: Takashi Iwai <tiwai@suse.de>
---
  I also had another generic patch prepared before I noticed Joe's
  quirk addition for the MS Lifecam HD-5000.

 sound/usb/quirks.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 753a47d..9a28365 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1113,8 +1113,13 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 
 bool snd_usb_get_sample_rate_quirk(struct snd_usb_audio *chip)
 {
-	/* MS Lifecam HD-5000 doesn't support reading the sample rate. */
-	return chip->usb_id == USB_ID(0x045E, 0x076D);
+	/* devices which do not support reading the sample rate. */
+	switch (chip->usb_id) {
+	case USB_ID(0x045E, 0x076D): /* MS Lifecam HD-5000 */
+	case USB_ID(0x04D8, 0xFEEA): /* Benchmark DAC1 Pre */
+		return true;
+	}
+	return false;
 }
 
 /* Marantz/Denon USB DACs need a vendor cmd to switch
-- 
EW

