linuxaudio.org

Robin Gareus wrote:

quoted text
> On 07/15/2010 01:07 PM, Ralf Mardorf wrote:

>> On Thu, 2010-07-15 at 12:55 +0200, Clemens Ladisch wrote:

>>> Ralf Mardorf wrote:

>>>> dev.hpet.max-user-freq

>>>

>>> This parameter will not have any effect on anything because there is no

>>> program that uses the HPET timers from userspace.

>

> That'd be correct if Ralf would stick to 'amidiplay' and friends for his

> tests.

>

> There are a couple of audio-tools who can use either RTC or HPET for

> timing, although most of them need an option to explicitly enable it.

Jack can read the current time from /dev/hpet, but it does not use it to

generate interrupts.  As far as I know, there is no program that does.
> BTW. Do you know the unit of these values?

quoted text
>   cat /sys/class/rtc/rtc0/max_user_freq

>   cat /proc/sys/dev/hpet/max-user-freq

> are they Hz?

Yes.
>> IIRC someone on jack-devel mailing list had issues when using mplayer

quoted text
>> with the value 64 and it was solved when using the value 1024.

This has nothing to do with MIDI timing; mplayer can use the RTC (not

HPET) for audio/video synchronization to work around the 100 Hz limit of

the system timer on old Linux kernels.
Regards,

Clemens

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