Re: [LAU] linux-rt & presonus 1818VSL

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To: Jeremy Jongepier <jeremy@...>
Cc: Linux Audio User <linux-audio-user@...>
Date: Wednesday, July 3, 2013 - 12:27 pm

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On Wed, Jul 3, 2013 at 8:43 AM, Jeremy Jongepier wrote:

> On 07/03/2013 12:19 AM, Harry van Haaren wrote:

Same here: I wrote that because its in my setup, and AFAIK its the kernel
timer... Just found this article:
https://www.kernel.org/doc/Documentation/rtc.txt It suggests that
/dev/rtc is the "old" RTC, and /dev/rtc0 /dev/rtc1 .. rtcX is the new
system. I have got /dev/rtc0 present on my system. I'll investigate into
whether JACK / the ALSA backend use /dev/rtc, or if it really isn't used
anymore.

> * Using setpci in this context is deprecated unless you're still using

I was advised on IRC that the PCI bandwidth reset would help, and it didn't
negatively influence my machine: hence I added it.

lspci -v -t shows that my firewire, cardbus ("CardBus bridge: Texas
Instruments PCIxx12 Cardbus Controller") SD card and multimedia card
readers are on the same branch, connected to the root node. I suppose
rm-modding those kernel modules would ensure better performance (not using
them probably suffices).

The graphics chip is on its own node, also connected directly to the root.
I don't think it'll get in the way.. Setting the latencies won't hurt, I'll
leave it there for now but add a note that on modern hardware its not
necessary.

Thanks for the feedback! -Harry

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On Wed, Jul 3, 2013 at 8:43 AM, Jeremy Jongepier =
<jeremy@autos=
tatic.com
> wrote:
On 07/03/2013 12:19 AM, Harry van Haaren wrote:
Nice article Harry! Some remarks though:
* Is /dev/rtc the kernel timer? I thought it was the device node for
access to the real-time clock. I don't even think it's necessary to=

prioritize it anymore because most applications use the kernel timer:
http://wiki.linuxaudio.org/wiki/system_configuratio=
n#hardware_timers

I'm far from an expert on timers so I could be wrong, I still find this=

a bit of esoteric stuff.Same here: I wrote that becau=
se its in my setup, and AFAIK its the kernel timer... Just found this artic=
le: https://ww=
w.kernel.org/doc/Documentation/rtc.txt
=A0=A0 It suggests that /dev/rtc =
is the "old" RTC, and /dev/rtc0 /dev/rtc1 .. rtcX is the new syst=
em. I have got /dev/rtc0 present on my system. I'll investigate into wh=
ether JACK / the ALSA backend use /dev/rtc, or if it really isn't used =
anymore.
=A0
* Using setpci in this context is deprecated unless you're still using<=
br>
am machine with a PCI bus which I highly doubt:
http://wiki.linuxaudio.org/wiki/system_configuratio=
n#pci_bus_latency
I was advised on IRC that the PC=
I bandwidth reset would help, and it didn't negatively influence my mac=
hine: hence I added it.
lspci -v -t shows that my firewire, cardbus ("CardBus bridge: Texa=
s Instruments PCIxx12 Cardbus Controller")=A0 SD card and multimedia c=
ard readers are on the same branch, connected to the root node. I suppose r=
m-modding those kernel modules would ensure better performance (not using t=
hem probably suffices).
The graphics chip is on its own node, also connec=
ted directly to the root. I don't think it'll get in the way.. Sett=
ing the latencies won't hurt, I'll leave it there for now but add a=
note that on modern hardware its not necessary.
Thanks for the feedback! -Harry

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Messages in current thread:
Re: [LAU] linux-rt &amp; presonus 1818VSL, Fero Kiraly, (Tue Jul 2, 6:43 pm)
Re: [LAU] linux-rt &amp; presonus 1818VSL, Jeremy Jongepier, (Wed Jul 3, 8:04 am)
Re: [LAU] linux-rt &amp; presonus 1818VSL, Harry van Haaren, (Tue Jul 2, 7:30 pm)
Re: [LAU] linux-rt &amp; presonus 1818VSL, Harry van Haaren, (Tue Jul 2, 10:19 pm)
Re: [LAU] linux-rt &amp; presonus 1818VSL, Jeremy Jongepier, (Wed Jul 3, 7:43 am)
Re: [LAU] linux-rt & presonus 1818VSL, Harry van Haaren, (Wed Jul 3, 12:27 pm)
Re: [LAU] Slightly O/T was: linux-rt &amp; presonus 1818VSL, Jeremy Jongepier, (Wed Jul 3, 1:35 pm)
Re: [LAU] Slightly O/T was: linux-rt &amp; presonus 1818VSL, Jeremy Jongepier, (Fri Jul 12, 7:46 am)
Re: [LAU] linux-rt &amp; presonus 1818VSL, Fero Kiraly, (Tue Jul 2, 10:26 pm)