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ALSA: usb-audio: UAC2: try to find and switch to valid clock

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If a selector is available on a device, it may be pointing to a
clock source which is currently invalid.
If there is a valid clock source which can be selected, switch
to it.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Eldad Zack 2013-04-03 23:18:55 +02:00 committed by Takashi Iwai
parent 06ffc1ebdd
commit 8c55af3f69
1 changed files with 66 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

69
sound/usb/clock.c
View file

@ -99,6 +99,41 @@ static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_i
return buf;
}
static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
unsigned char pin)
{
int ret;
ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
UAC2_CS_CUR,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
UAC2_CX_CLOCK_SELECTOR << 8,
snd_usb_ctrl_intf(chip) | (selector_id << 8),
&pin, sizeof(pin));
if (ret < 0)
return ret;
if (ret != sizeof(pin)) {
snd_printk(KERN_ERR
"usb-audio:%d: setting selector (id %d) unexpected length %d\n",
chip->dev->devnum, selector_id, ret);
return -EINVAL;
}
ret = uac_clock_selector_get_val(chip, selector_id);
if (ret < 0)
return ret;
if (ret != pin) {
snd_printk(KERN_ERR
"usb-audio:%d: setting selector (id %d) to %x failed (current: %d)\n",
chip->dev->devnum, selector_id, pin, ret);
return -EINVAL;
}
return ret;
}
static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
{
int err;
@ -161,7 +196,7 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
if (selector) {
int ret;
int ret, i, cur;
/* the entity ID we are looking for is a selector.
* find out what it currently selects */
@ -179,8 +214,35 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
return -EINVAL;
}
return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
cur = ret;
ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],
visited, validate);
if (!validate || ret > 0)
return ret;
/* The current clock source is invalid, try others. */
for (i = 1; i <= selector->bNrInPins; i++) {
int err;
if (i == cur)
continue;
ret = __uac_clock_find_source(chip, selector->baCSourceID[i - 1],
visited, true);
if (ret < 0)
continue;
err = uac_clock_selector_set_val(chip, entity_id, i);
if (err < 0)
continue;
snd_printk(KERN_INFO
"usb-audio:%d: found and selected valid clock source %d\n",
chip->dev->devnum, ret);
return ret;
}
return -ENXIO;
}
/* FIXME: multipliers only act as pass-thru element for now */
@ -284,8 +346,9 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
struct usb_device *dev = chip->dev;
__le32 data;
int err, cur_rate, prev_rate;
int clock = snd_usb_clock_find_source(chip, fmt->clock, true);
int clock;
clock = snd_usb_clock_find_source(chip, fmt->clock, true);
if (clock < 0)
return clock;