At Thu, 3 Sep 2009 17:35:43 +0200,Giovanni Maruzzelli wrote:> > On Thu, Sep 3, 2009 at 5:29 PM, Takashi Iwai<tiwai@xxxxxxx> wrote:> >> Sep 3 17:20:20 localhost kernel: giovanni line: 291, dpcm->frac_pos /> >> HZ=0, jiffies=91837395> >> Sep 3 17:20:20 localhost kernel: giovanni line: 291, dpcm->frac_pos /> >> HZ=48, jiffies=91837398> >> Sep 3 17:20:20 localhost kernel: giovanni line: 291, dpcm->frac_pos /> >> HZ=48, jiffies=91837398> >> Sep 3 17:20:20 localhost kernel: giovanni line: 291, dpcm->frac_pos /> >> HZ=80, jiffies=91837400> >> Sep 3 17:20:20 localhost kernel: giovanni line: 291, dpcm->frac_pos /> >> HZ=80, jiffies=91837400> >> > So, this is a kernel with the variable HZ. That's the whole problem.> > My patch also doesn't take it into account but assumes the constant HZ.> > We'll need to convert the stuff to msecs_to_jiffies() and co...> > Ah! I was struggling since days on this, you're fast!!!> > Also, I saw you made various modifications that I tried to make (in a> messy way), to a custom version of snd-dummy made to support 128> subdevices and use less irq and context switches.> As soon as you looked into the variable HZ problem, I will see if my> modifications still make some sense, and in case I will forward it to> you.
Try the patch below. It just converts the calculation base to msecinstead of HZ.
The enhancement to max 128 subdevices should be easy. Isn't it sufficeto define MAX_PCM_SUBSTREAMS to 128?
Takashi
---diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.cindex 0a798bd..fd5f753 100644--- a/sound/drivers/dummy.c+++ b/sound/drivers/dummy.c@@ -206,9 +206,9 @@ struct dummy_systimer_pcm { spinlock_t lock; struct timer_list timer; unsigned long base_time;- unsigned int frac_pos; /* fractional sample position (based HZ) */- unsigned int frac_buffer_size; /* buffer_size * HZ */- unsigned int frac_period_size; /* period_size * HZ */+ unsigned int frac_pos; /* fractional sample position (based in msec) */+ unsigned int frac_buffer_size; /* buffer_size * 1000 */+ unsigned int frac_period_size; /* period_size * 1000 */ unsigned int rate; struct snd_pcm_substream *substream; };@@ -218,8 +218,8 @@ static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm) unsigned long frac; frac = dpcm->frac_pos % dpcm->frac_period_size;- dpcm->timer.expires = jiffies +- (dpcm->frac_period_size + dpcm->rate - 1) / dpcm->rate;+ frac = (dpcm->frac_period_size - frac + dpcm->rate - 1) / dpcm->rate;+ dpcm->timer.expires = jiffies + msecs_to_jiffies(frac); add_timer(&dpcm->timer); } @@ -231,6 +231,7 @@ static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm) if (!delta) return; dpcm->base_time = jiffies;+ delta = jiffies_to_msecs(delta); dpcm->frac_pos += delta * dpcm->rate; while (dpcm->frac_pos >= dpcm->frac_buffer_size) dpcm->frac_pos -= dpcm->frac_buffer_size;@@ -262,8 +263,8 @@ static int dummy_systimer_prepare(struct snd_pcm_substream *substream) dpcm->frac_pos = 0; dpcm->rate = runtime->rate;- dpcm->frac_buffer_size = runtime->buffer_size * HZ;- dpcm->frac_period_size = runtime->period_size * HZ;+ dpcm->frac_buffer_size = runtime->buffer_size * 1000;+ dpcm->frac_period_size = runtime->period_size * 1000; return 0; }@@ -288,7 +289,7 @@ dummy_systimer_pointer(struct snd_pcm_substream *substream) spin_lock(&dpcm->lock); dummy_systimer_update(dpcm); spin_unlock(&dpcm->lock);- return dpcm->frac_pos / HZ;+ return dpcm->frac_pos / 1000; } static int dummy_systimer_create(struct snd_pcm_substream *substream)_______________________________________________Alsa-devel mailing listAlsa-devel@xxxxxxxxxxxxxxxxxxxx://mailman.alsa-project.org/mailman/listinfo/alsa-devel
