[PATCH RFC 3/4] snd-usb-audio: Trust fields given in the quirk

[Mark Hills <mark@xwax.org>]

The maxpacksize field is given in some quirks, but it gets ignored
(in favour of wMaxPacketSize from the first endpoint.) This patch
favours the one in the quirk.

Digidesign Mbox and Mbox 2 are the only affected quirks and the
devices are assumed to be working without this patch. So for safety
against the values in the quirk being incorrect, remove them.

The datainterval is also ignored but there are not currently any
quirks which choose to override this.

Cc: Damien Zammit <damien@zamaudio.com>
Cc: Chris J Arges <christopherarges@gmail.com>
---
 sound/usb/quirks-table.h | 3 ---
 sound/usb/quirks.c       | 6 ++++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 1c8db85..3614e9b 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2965,7 +2965,6 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
 					.endpoint = 0x02,
 					.ep_attr = 0x01,
-					.maxpacksize = 0x130,
 					.rates = SNDRV_PCM_RATE_44100 |
 						 SNDRV_PCM_RATE_48000,
 					.rate_min = 44100,
@@ -3013,7 +3012,6 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 					.attributes = 0x00,
 					.endpoint = 0x03,
 					.ep_attr = USB_ENDPOINT_SYNC_ASYNC,
-					.maxpacksize = 0x128,
 					.rates = SNDRV_PCM_RATE_48000,
 					.rate_min = 48000,
 					.rate_max = 48000,
@@ -3039,7 +3037,6 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
 					.endpoint = 0x85,
 					.ep_attr = USB_ENDPOINT_SYNC_SYNC,
-					.maxpacksize = 0x128,
 					.rates = SNDRV_PCM_RATE_48000,
 					.rate_min = 48000,
 					.rate_max = 48000,
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index b0f7140..0745eea 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -165,8 +165,10 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
 		return -EINVAL;
 	}
 	alts = &iface->altsetting[fp->altset_idx];
-	fp->datainterval = snd_usb_parse_datainterval(chip, alts);
-	fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+	if (fp->datainterval == 0)
+		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+	if (fp->maxpacksize == 0)
+		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
 	usb_set_interface(chip->dev, fp->iface, 0);
 	snd_usb_init_pitch(chip, fp->iface, alts, fp);
 	snd_usb_init_sample_rate(chip, fp->iface, alts, fp, fp->rate_max);
-- 
1.7.12.1