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authorTakashi Iwai <tiwai@suse.de>2018-05-02 09:36:28 +0200
committerTakashi Iwai <tiwai@suse.de>2018-05-02 16:02:33 +0200
commitb099b9693d23d035c77c218508e083484ff63024 (patch)
treee5146fb1601205061cf55e0f82d01cac5c513e47 /sound/usb
parent964af639ad699404cbe36d0c1fc85970700e6107 (diff)
ALSA: usb-audio: Avoid superfluous usb_set_interface() calls
This is a preliminary change for the upcoming quirk implementation. Currently USB-audio driver tries to call usb_set_interface() whenever the format change with interface/altset modification happens. In this patch, the check is replaced with the comparison of cur_altsetting and the targeted altsetting pointer, so that the driver may skip the unnecessary function calls. Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/pcm.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index ad39b3cca247..ae7d8a0a0a0a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -499,7 +499,7 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
iface = usb_ifnum_to_if(dev, fmt->iface);
if (WARN_ON(!iface))
return -EINVAL;
- alts = &iface->altsetting[fmt->altset_idx];
+ alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
altsd = get_iface_desc(alts);
if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
return -EINVAL;
@@ -521,9 +521,7 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
}
/* set interface */
- if (subs->interface != fmt->iface ||
- subs->altset_idx != fmt->altset_idx) {
-
+ if (iface->cur_altsetting != alts) {
err = snd_usb_select_mode_quirk(subs, fmt);
if (err < 0)
return -EIO;
@@ -537,12 +535,11 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
}
dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
fmt->iface, fmt->altsetting);
- subs->interface = fmt->iface;
- subs->altset_idx = fmt->altset_idx;
-
snd_usb_set_interface_quirk(dev);
}
+ subs->interface = fmt->iface;
+ subs->altset_idx = fmt->altset_idx;
subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
alts, fmt->endpoint, subs->direction,
SND_USB_ENDPOINT_TYPE_DATA);