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ALSA: usb-audio: Add boot quirk for Behringer CM1A

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After a power cycle and reenumeration, the Behringer CM1A* leaves its
MIDI endpoint inoperative. USB enumeration and driver binding
complete successfully, but MIDI outputs remain pending.

A GET_DESCRIPTOR request for the device descriptor, issued after USB
configuration, makes the endpoint operational. Add a one time boot quirk
to perform that request before ALSA initializes the device.

*
ID 1397:1234 BEHRINGER International GmbH CM1A

Signed-off-by: Sebastian Dalfuß <sd@sedf.de>
Link: https://patch.msgid.link/apwG4DRfNyvmRzyb@sedf.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Sebastian Dalfuß 2026-09-05 14:11:12 +02:00 committed by Takashi Iwai
parent 12cba0ce11
commit 45b5beb60b
1 changed files with 23 additions and 0 deletions
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23
sound/usb/quirks.c
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@ -849,6 +849,27 @@ static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
return 0;
}
/*
* A post configuration device descriptor read is needed to make the CM1A
* operational after reenumeration.
*/
static int snd_usb_cm1a_boot_quirk(struct usb_device *dev)
{
struct usb_device_descriptor *desc __free(kfree) = kmalloc_obj(*desc);
int err;
if (!desc)
return -ENOMEM;
err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, sizeof(*desc));
if (err < 0) {
dev_err(&dev->dev, "failed to read device descriptor: %d\n", err);
return err;
}
return 0;
}
/*
* Some sound cards from Native Instruments are in fact compliant to the USB
* audio standard of version 2 and other approved USB standards, even though
@ -1681,6 +1702,8 @@ int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
switch (id) {
case USB_ID(0x07fd, 0x0008): /* MOTU M Series, 1st hardware version */
return snd_usb_motu_m_series_boot_quirk(dev);
case USB_ID(0x1397, 0x1234): /* Behringer CM1A */
return snd_usb_cm1a_boot_quirk(dev);
}
return 0;