path: root/sound/usb/usbaudio.h
diff options
authorTakashi Iwai <tiwai@suse.de>2021-01-08 08:52:17 +0100
committerTakashi Iwai <tiwai@suse.de>2021-01-08 23:43:37 +0100
commit00272c61827e37bb64c47499843d8c0d8ee136a5 (patch)
tree4ef81c40a22801287f9803432dc3a61a7135850b /sound/usb/usbaudio.h
parentALSA: usb-audio: Choose audioformat of a counter-part substream (diff)
ALSA: usb-audio: Avoid unnecessary interface re-setup
The current endpoint handling assumed (more or less) a unique 1:1 relation between the endpoint and the iface/altset. The exception was the sync EP without the implicit feedback which has usually the secondary EP of the same altset. This works fine for most devices, but it turned out that some unusual devices like Pinoeer's ones have both playback and capture endpoints in the same iface/altsetting and use both for the implicit feedback mode. For handling such a case, we need to extend the endpoint management to take the shared interface into account. This patch does that: it adds a new object snd_usb_iface_ref for managing the reference counts of the each USB interface that is used by each endpoint. The interface setup is performed only once for the (sharing) endpoints, and the doubly initialization is avoided. Along with this, the resource release of endpoints and interface refcounts are put into a single function, snd_usb_endpoint_free_all() instead of looping in the caller side. Fixes: bf6313a0ff76 ("ALSA: usb-audio: Refactor endpoint management") Link: https://lore.kernel.org/r/20210108075219.21463-4-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/usbaudio.h')
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 980287aadd36..215c1771dd57 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -44,6 +44,7 @@ struct snd_usb_audio {
struct list_head pcm_list; /* list of pcm streams */
struct list_head ep_list; /* list of audio-related endpoints */
+ struct list_head iface_ref_list; /* list of interface refcounts */
int pcm_devs;
struct list_head midi_list; /* list of midi interfaces */