ALSA: usb-audio: UAC2: auto clock selection module param
Add a module param to disable auto clock selection.
This is provided for users that expect the audio stream to
fail when the clock source is invalid (e.g., the word clock
was unintentionally disconnected).
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 314e8a2..5254b18 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -82,6 +82,7 @@
static int nrpacks = 8; /* max. number of packets per urb */
static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
static bool ignore_ctl_error;
+static bool autoclock = true;
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
@@ -100,6 +101,8 @@
module_param(ignore_ctl_error, bool, 0444);
MODULE_PARM_DESC(ignore_ctl_error,
"Ignore errors from USB controller for mixer interfaces.");
+module_param(autoclock, bool, 0444);
+MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
/*
* we keep the snd_usb_audio_t instances by ourselves for merging
@@ -354,6 +357,7 @@
chip->card = card;
chip->setup = device_setup[idx];
chip->nrpacks = nrpacks;
+ chip->autoclock = autoclock;
chip->probing = 1;
chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index d7ab2d75..e59d359 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -217,7 +217,7 @@
cur = ret;
ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],
visited, validate);
- if (!validate || ret > 0)
+ if (!validate || ret > 0 || !chip->autoclock)
return ret;
/* The current clock source is invalid, try others. */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 1ac3fd9..bc43bca 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -56,6 +56,7 @@
int setup; /* from the 'device_setup' module param */
int nrpacks; /* from the 'nrpacks' module param */
+ bool autoclock; /* from the 'autoclock' module param */
struct usb_host_interface *ctrl_intf; /* the audio control interface */
};
