[LAU] RTC/HPET timer permissions

Clemens Ladisch clemens at ladisch.de
Mon Nov 26 14:03:47 UTC 2012


Jeremy Jongepier wrote:
> On 11/25/2012 01:23 PM, Clemens Ladisch wrote:
>> Using the RTC or HPET devices directly is necessary only if
>> the kernel does not use them for timers.  Nowadays, kernels do, and
>> applications use the proper timer APIs.
>
> What are those timer API's?

POSIX timers, interval timers, nanosleep(), usleep(), poll() timeout.

>> You'd need this only if you're using some audio application that hasn't
>> been updated for many years.
>
> So this section has become deprecated?
> http://wiki.linuxmusicians.com/doku.php?id=system_configuration#hardware_timers

Only if all applications actually have been updated.
Wasn't there some sequencer (Rosegarden? Muse?) that still uses RTC?

> And how does the snd-hrtimer module relate to this matter?

It's for some timers used internally by ALSA, and loaded automatically.


Regards,
Clemens


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