Re: [LAU] XanMod kernel

From: Jeremy Jongepier <jeremy@email-addr-hidden>
Date: Tue Jun 09 2020 - 18:27:59 EEST

Hello Tim,

> My understanding is that ALSA placed a hard-coded limit on the
>  snd-hrtimer of around 1024Hz a couple of years ago.
>
> The snd-hrtimer used to be able to be set very high frequencies
>  until one day it wouldn't. I contacted ALSA and they told me
>  about this new hard-coded limit.
>
> This sent me scrambling to re-order the midi timer preference
>  in MusE because it seems the RTC timer is now the only timer
>  that can give you anything above 1024Hz.
>
> Have I got this correct?

I checked sound/core/hrtimer.c of a current linux kernel source and I
don't see any limits of 1000 or 1024. And when I check on my system with
`cat /proc/asound/timers` I see the resolution of the system timer is
1000 µs, so 1 ms (which I think equals the 1000 HZ kernel setting I use)
while the HR timer has a resolution of 0.001 µs, so 1 ns. If I search
for .resolution in /proc/timer_list I see that same value, so 1 ns. So
my guess is that snd-hrtimer goes way beyond 1000 HZ and doesn't seem to
have a hard-coded limit of itself.

Best,

Jeremy

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Received on Wed Jun 10 04:15:03 2020

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