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| author |   Takashi Iwai <tiwai@suse.de> | 2021-08-29 09:38:30 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-08-29 09:41:27 +0200 |
| commit | 4801bee7d5a36c199b734a28cde5259183aff822 (patch) | |
| tree | 106e13cacf6d6263316ff0147734465037e90cd8 /sound/usb/card.c | |
| parent | ALSA: usb-audio: Work around for XRUN with low latency playback (diff) | |
| download | linux-dev-4801bee7d5a36c199b734a28cde5259183aff822.tar.xz linux-dev-4801bee7d5a36c199b734a28cde5259183aff822.zip | |
ALSA: usb-audio: Add lowlatency module option
For making user to switch back to the old playback mode, this patch
adds a new module option 'lowlatency' to snd-usb-audio driver.
When user face a regression due to the recent low-latency playback
support, they can test easily by passing lowlatency=0 option without
rebuilding the kernel.
Fixes: 307cc9baac5c ("ALSA: usb-audio: Reduce latency at playback start, take#2")
Link: https://lore.kernel.org/r/20210829073830.22686-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/card.c')
| -rw-r--r-- | sound/usb/card.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c index a1f8c3a026f5..6abfc9d079e7 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -68,6 +68,7 @@ static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; static int device_setup[SNDRV_CARDS]; /* device parameter for this card */ static bool ignore_ctl_error; static bool autoclock = true; +static bool lowlatency = true; static char *quirk_alias[SNDRV_CARDS]; static char *delayed_register[SNDRV_CARDS]; static bool implicit_fb[SNDRV_CARDS]; @@ -92,6 +93,8 @@ 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)."); +module_param(lowlatency, bool, 0444); +MODULE_PARM_DESC(lowlatency, "Enable low latency playback (default: yes)."); module_param_array(quirk_alias, charp, NULL, 0444); MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef."); module_param_array(delayed_register, charp, NULL, 0444); @@ -599,6 +602,7 @@ static int snd_usb_audio_create(struct usb_interface *intf, chip->setup = device_setup[idx]; chip->generic_implicit_fb = implicit_fb[idx]; chip->autoclock = autoclock; + chip->lowlatency = lowlatency; atomic_set(&chip->active, 1); /* avoid autopm during probing */ atomic_set(&chip->usage_count, 0); atomic_set(&chip->shutdown, 0); |