2009/12/8 Takashi Iwai <tiwai@xxxxxxx>
> At Sat, 5 Dec 2009 10:17:07 +0800,
> Raymond Yau wrote:
> >
> > 2009/12/4 pl bossart <bossart.nospam@xxxxxxxxx>
> >
> > > >> 17. hwptr 24351 buffer 16384 appl 24332, avail=16403
> > > >
> > > > appl pointer is behind hwprtr ( underrun ) , need timestamp to find
> out
> > > > whether PA is unable to write audio data in time since
> > >
> > > I commented out the portion of the code that increases the watermark
> and
> > > clamped the number of available samples to the buffer size, and it
> works
> > > just fine, no audio
> > > underflows.
> > >
> >
> > Do you mean that the underrun is related the the portion of code that
> > increase the watermark (i.e It is a pulseaudio bug instead of driver bug
> )
> > ?
>
> Or, we can try simply to change to periods_min = 2 whether this fixes
> the PA issues.
>
> periods_min = 1 is anyway fairly fragile. With that setup, apps are
> supposed (implicitly) to wake up frequently enough to get pointers in
> sync. This is because you can't trust whether the IRQ wake up is
> really fast enough. There are machines that aren't.
>
>
> thanks,
>
> Takashi
>
The intel8x0 driver has code to handle one period per buffer ,
Is the feature "one period per buffer" designed for dmix ?
static void snd_intel8x0_setup_periods(struct intel8x0 *chip, struct
ichdev *ichdev)
{
int idx;
u32 *bdbar = ichdev->bdbar;
unsigned long port = ichdev->reg_offset;
iputdword(chip, port + ICH_REG_OFF_BDBAR, ichdev->bdbar_addr);
if (ichdev->size == ichdev->fragsize) {
ichdev->ack_reload = ichdev->ack = 2;
ichdev->fragsize1 = ichdev->fragsize >> 1;
for (idx = 0; idx < (ICH_REG_LVI_MASK + 1) * 2; idx += 4) {
bdbar[idx + 0] = cpu_to_le32(ichdev->physbuf);
bdbar[idx + 1] = cpu_to_le32(0x80000000 | /* interrupt on completion */
ichdev->fragsize1 >> ichdev->pos_shift);
bdbar[idx + 2] = cpu_to_le32(ichdev->physbuf + (ichdev->size >> 1));
bdbar[idx + 3] = cpu_to_le32(0x80000000 | /* interrupt on completion */
ichdev->fragsize1 >> ichdev->pos_shift);
}
ichdev->frags = 2;
} else {
The system timer may be running faster or slower than the sound card
on differnt machine
PA only adjust the watermark/sleeping time in one direction only
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