Subject: Re: [linux-audio-dev] minimum tick time
From: Takashi Iwai (tiwai_AT_suse.de)
Date: Tue Nov 06 2001 - 19:40:33 EET
Hi Maarten,
At Tue, 6 Nov 2001 17:12:01 +0100,
Maarten de Boer wrote:
>
> Hello,
>
> I am trying to get low latency with alsa.
> I have kernel 2.4.13 with the preemptive patch and the
> alsa-driver/utils/patches/rtc-2.4.9.dif patch applied.
> In the kernel configuration, I turned on RTC and
> Preemptive.
>
> I run the alsa-lib/test/latency.c test in poll mode,
> but the problem is the tick time, which is at 100 Hz:
>
> snd_pcm_hw_params_get_tick_time(params, NULL) = 10000
>
> What am I doing wrong?
The timer invoked by pcm is only system timer, so resolution is fixed
as HZ. IMO, it would be nice to make it available to use other timer
sources, but this will lead to major rewrite..
(Cc'ed to alsa-devel, since it's more specific to alsa itself.)
ciao,
Takashi
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