ALSA: usb-audio: Create a registration quirk for Kingston HyperX Amp (0951:16d8)

Create a quirk that allows special processing and/or
skipping the call to snd_card_register.

For HyperX AMP, which uses two interfaces, but only has
a capture stream in the second, this allows the capture
stream to merge with the first PCM.

Signed-off-by: Chris Wulff <crwulff@gmail.com>
Link: https://lore.kernel.org/r/20200314165449.4086-3-crwulff@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 827fb0bc8b56199125fc048f0510774d42a82ac6..16bbe2a50fb7b536144af729bb157221b871266c 100644 (file)
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -662,10 +662,14 @@ static int usb_audio_probe(struct usb_interface *intf,
                        goto __error;
        }
 
-       /* we are allowed to call snd_card_register() many times */
-       err = snd_card_register(chip->card);
-       if (err < 0)
-               goto __error;
+       /* we are allowed to call snd_card_register() many times, but first
+        * check to see if a device needs to skip it or do anything special
+        */
+       if (snd_usb_registration_quirk(chip, ifnum) == 0) {
+               err = snd_card_register(chip->card);
+               if (err < 0)
+                       goto __error;
+       }
 
        if (quirk && quirk->shares_media_device) {
                /* don't want to fail when snd_media_device_create() fails */

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 3cc745fe24d8dd9c3a104f863f1b2c3177949ab7..d605aff801b84805fb9b7c42bcc3223dc9cc74e0 100644 (file)
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1808,3 +1808,17 @@ void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
                break;
        }
 }
+
+int snd_usb_registration_quirk(struct snd_usb_audio *chip,
+                              int iface)
+{
+       switch (chip->usb_id) {
+       case USB_ID(0x0951, 0x16d8): /* Kingston HyperX AMP */
+               /* Register only when we reach interface 2 so that streams can
+                * merge correctly into PCMs from interface 0
+                */
+               return (iface != 2);
+       }
+       /* Register as normal */
+       return 0;
+}

diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index df0355843a4c153010a27d7c9389445093c908a2..3afc01eabc7e2a5aecd603488bde35002df050c9 100644 (file)
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -51,4 +51,7 @@ void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
                                          struct audioformat *fp,
                                          int stream);
 
+int snd_usb_registration_quirk(struct snd_usb_audio *chip,
+                              int iface);
+
 #endif /* __USBAUDIO_QUIRKS_H */