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sound: usb-audio: allow period sizes less than 1 ms

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To enable periods shorter than 1 ms, we have to make sure that short
periods are only available for alternate settings that have a small
enough data packet interval.  Furthermore, the code that aligns URBs to
USB frames is now superfluous.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2009-04-03 09:48:26 +02:00 committed by Takashi Iwai
parent 744b89e542
commit a7d9c0990d
1 changed files with 86 additions and 20 deletions
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106
sound/usb/usbaudio.c
View file

@ -171,7 +171,6 @@ struct snd_usb_substream {
unsigned int curframesize; /* current packet size in frames (for capture) */
unsigned int fill_max: 1; /* fill max packet size always */
unsigned int fmt_type; /* USB audio format type (1-3) */
unsigned int packs_per_ms; /* packets per millisecond (for playback) */
unsigned int running: 1; /* running status */
@ -608,9 +607,7 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
break;
}
}
/* finish at the frame boundary at/after the period boundary */
if (period_elapsed &&
(i & (subs->packs_per_ms - 1)) == subs->packs_per_ms - 1)
if (period_elapsed) /* finish at the period boundary */
break;
}
if (subs->hwptr_done + offs > runtime->buffer_size) {
@ -1068,7 +1065,6 @@ static int init_substream_urbs(struct snd_usb_substream *subs, unsigned int peri
packs_per_ms = 8 >> subs->datainterval;
else
packs_per_ms = 1;
subs->packs_per_ms = packs_per_ms;
if (is_playback) {
urb_packs = max(nrpacks, 1);
@ -1088,18 +1084,17 @@ static int init_substream_urbs(struct snd_usb_substream *subs, unsigned int peri
minsize -= minsize >> 3;
minsize = max(minsize, 1u);
total_packs = (period_bytes + minsize - 1) / minsize;
/* round up to multiple of packs_per_ms */
total_packs = (total_packs + packs_per_ms - 1)
& ~(packs_per_ms - 1);
/* we need at least two URBs for queueing */
if (total_packs < 2 * packs_per_ms) {
total_packs = 2 * packs_per_ms;
if (total_packs < 2) {
total_packs = 2;
} else {
/* and we don't want too long a queue either */
maxpacks = max(MAX_QUEUE * packs_per_ms, urb_packs * 2);
total_packs = min(total_packs, maxpacks);
}
} else {
while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
urb_packs >>= 1;
total_packs = MAX_URBS * urb_packs;
}
subs->nurbs = (total_packs + urb_packs - 1) / urb_packs;
@ -1564,11 +1559,15 @@ static struct snd_pcm_hardware snd_usb_hardware =
#define hwc_debug(fmt, args...) /**/
#endif
static int hw_check_valid_format(struct snd_pcm_hw_params *params, struct audioformat *fp)
static int hw_check_valid_format(struct snd_usb_substream *subs,
struct snd_pcm_hw_params *params,
struct audioformat *fp)
{
struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
unsigned int ptime;
/* check the format */
if (!snd_mask_test(fmts, fp->format)) {
@ -1589,6 +1588,14 @@ static int hw_check_valid_format(struct snd_pcm_hw_params *params, struct audiof
hwc_debug(" > check: rate_max %d < min %d\n", fp->rate_max, it->min);
return 0;
}
/* check whether the period time is >= the data packet interval */
if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH) {
ptime = 125 * (1 << fp->datainterval);
if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
hwc_debug(" > check: ptime %u > max %u\n", ptime, pt->max);
return 0;
}
}
return 1;
}
@ -1607,7 +1614,7 @@ static int hw_rule_rate(struct snd_pcm_hw_params *params,
list_for_each(p, &subs->fmt_list) {
struct audioformat *fp;
fp = list_entry(p, struct audioformat, list);
if (!hw_check_valid_format(params, fp))
if (!hw_check_valid_format(subs, params, fp))
continue;
if (changed++) {
if (rmin > fp->rate_min)
@ -1661,7 +1668,7 @@ static int hw_rule_channels(struct snd_pcm_hw_params *params,
list_for_each(p, &subs->fmt_list) {
struct audioformat *fp;
fp = list_entry(p, struct audioformat, list);
if (!hw_check_valid_format(params, fp))
if (!hw_check_valid_format(subs, params, fp))
continue;
if (changed++) {
if (rmin > fp->channels)
@ -1714,7 +1721,7 @@ static int hw_rule_format(struct snd_pcm_hw_params *params,
list_for_each(p, &subs->fmt_list) {
struct audioformat *fp;
fp = list_entry(p, struct audioformat, list);
if (!hw_check_valid_format(params, fp))
if (!hw_check_valid_format(subs, params, fp))
continue;
fbits |= (1ULL << fp->format);
}
@ -1732,6 +1739,44 @@ static int hw_rule_format(struct snd_pcm_hw_params *params,
return changed;
}
static int hw_rule_period_time(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct snd_usb_substream *subs = rule->private;
struct audioformat *fp;
struct snd_interval *it;
unsigned char min_datainterval;
unsigned int pmin;
int changed;
it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
min_datainterval = 0xff;
list_for_each_entry(fp, &subs->fmt_list, list) {
if (!hw_check_valid_format(subs, params, fp))
continue;
min_datainterval = min(min_datainterval, fp->datainterval);
}
if (min_datainterval == 0xff) {
hwc_debug(" --> get emtpy\n");
it->empty = 1;
return -EINVAL;
}
pmin = 125 * (1 << min_datainterval);
changed = 0;
if (it->min < pmin) {
it->min = pmin;
it->openmin = 0;
changed = 1;
}
if (snd_interval_checkempty(it)) {
it->empty = 1;
return -EINVAL;
}
hwc_debug(" --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
return changed;
}
/*
* If the device supports unusual bit rates, does the request meet these?
*/
@ -1777,6 +1822,8 @@ static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
{
struct list_head *p;
unsigned int pt, ptmin;
int param_period_time_if_needed;
int err;
runtime->hw.formats = subs->formats;
@ -1786,6 +1833,7 @@ static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substre
runtime->hw.channels_min = 256;
runtime->hw.channels_max = 0;
runtime->hw.rates = 0;
ptmin = UINT_MAX;
/* check min/max rates and channels */
list_for_each(p, &subs->fmt_list) {
struct audioformat *fp;
@ -1804,34 +1852,52 @@ static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substre
runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
fp->frame_size;
}
pt = 125 * (1 << fp->datainterval);
ptmin = min(ptmin, pt);
}
/* set the period time minimum 1ms */
/* FIXME: high-speed mode allows 125us minimum period, but many parts
* in the current code assume the 1ms period.
*/
param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
if (snd_usb_get_speed(subs->dev) != USB_SPEED_HIGH)
/* full speed devices have fixed data packet interval */
ptmin = 1000;
if (ptmin == 1000)
/* if period time doesn't go below 1 ms, no rules needed */
param_period_time_if_needed = -1;
snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1000,
/*(nrpacks * MAX_URBS) * 1000*/ UINT_MAX);
ptmin, UINT_MAX);
if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
hw_rule_rate, subs,
SNDRV_PCM_HW_PARAM_FORMAT,
SNDRV_PCM_HW_PARAM_CHANNELS,
param_period_time_if_needed,
-1)) < 0)
return err;
if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
hw_rule_channels, subs,
SNDRV_PCM_HW_PARAM_FORMAT,
SNDRV_PCM_HW_PARAM_RATE,
param_period_time_if_needed,
-1)) < 0)
return err;
if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
hw_rule_format, subs,
SNDRV_PCM_HW_PARAM_RATE,
SNDRV_PCM_HW_PARAM_CHANNELS,
param_period_time_if_needed,
-1)) < 0)
return err;
if (param_period_time_if_needed >= 0) {
err = snd_pcm_hw_rule_add(runtime, 0,
SNDRV_PCM_HW_PARAM_PERIOD_TIME,
hw_rule_period_time, subs,
SNDRV_PCM_HW_PARAM_FORMAT,
SNDRV_PCM_HW_PARAM_CHANNELS,
SNDRV_PCM_HW_PARAM_RATE,
-1);
if (err < 0)
return err;
}
if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)
return err;
return 0;