[alsa-devel] [PATCH] ALSA: usb-audio: Add boot quirk for MOTU M Series

[Alexander Tsoy]

Add delay to make sure that audio urbs are not sent too early.
Otherwise the device hangs. Windows driver makes ~2s delay, so use
about the same time delay value.

snd_usb_apply_boot_quirk() is called 3 times for my MOTU M4, which
is an overkill. Thus a quirk that is called only once is implemented.

Also send two vendor-specific control messages before and after
the delay. This behaviour is blindly copied from the Windows driver.

Signed-off-by: Alexander Tsoy <alexander at tsoy.me>
---
 sound/usb/card.c   |  4 ++++
 sound/usb/quirks.c | 38 ++++++++++++++++++++++++++++++++++++++
 sound/usb/quirks.h |  5 +++++
 3 files changed, 47 insertions(+)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 9f743ebae615..2f582ac7cf78 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -600,6 +600,10 @@ static int usb_audio_probe(struct usb_interface *intf,
 		}
 	}
 	if (! chip) {
+		err = snd_usb_apply_boot_quirk_once(dev, intf, quirk, id);
+		if (err < 0)
+			return err;
+
 		/* it's a fresh one.
 		 * now look for an empty slot and create a new card instance
 		 */
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 82184036437b..c93c53126243 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1113,6 +1113,31 @@ static int snd_usb_motu_microbookii_boot_quirk(struct usb_device *dev)
 	return err;
 }
 
+static int snd_usb_motu_m_series_boot_quirk(struct usb_device *dev)
+{
+	int ret;
+
+	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
+		return -EINVAL;
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      1, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      0x0, 0, NULL, 0, 1000);
+
+	if (ret < 0)
+		return ret;
+
+	msleep(2000);
+
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      1, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      0x20, 0, NULL, 0, 1000);
+
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 /*
  * Setup quirks
  */
@@ -1297,6 +1322,19 @@ int snd_usb_apply_boot_quirk(struct usb_device *dev,
 	return 0;
 }
 
+int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
+			          struct usb_interface *intf,
+			          const struct snd_usb_audio_quirk *quirk,
+			          unsigned int id)
+{
+	switch (id) {
+	case USB_ID(0x07fd, 0x0008): /* MOTU M Series */
+		return snd_usb_motu_m_series_boot_quirk(dev);
+	}
+
+	return 0;
+}
+
 /*
  * check if the device uses big-endian samples
  */
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index a80e0ddd0736..fa83a98ad7bb 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -20,6 +20,11 @@ int snd_usb_apply_boot_quirk(struct usb_device *dev,
 			     const struct snd_usb_audio_quirk *quirk,
 			     unsigned int usb_id);
 
+int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
+			          struct usb_interface *intf,
+			          const struct snd_usb_audio_quirk *quirk,
+			          unsigned int usb_id);
+
 void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 			      struct audioformat *fmt);
 
-- 
2.24.1