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I recently installed the latest version of AV Linux on a 32 bit older ACER 9410Z laptop.  I have been running KXStudio for years (Ubuntu Studio before that) and wanted to see if an RT kernel would help. 

I run Cantabile Lite version 2 and use that to host various Windows VSTi's on KXStudio and play live gigs with that setup.  I was able to get Cantabile Lite working on AVLinux as well. So far so good. I use Jack/Alsa and have never used Pulse Audio at all because I never found it would play nice with the distros I was using. I was a "bad boy" and removed Pulse Audio from AV Linux after the install.

When I installed OMB12, which is an arranger keyboard simulation program, I noticed that I don't have the options to install VSTi's within the program and the midi output choices are very limited.  Cantabile also does not "see" many Midi port options like it does in KXStudio.  It seems that AV Linux is not making those other midi options available.

When I try to start the Alsa-Midi Bridge using CATIA, it does not start.  I suspect that is where my current issue lies.
Any suggestions? Keep in mind I am only seeing midi through port 0 and cannot start the Alsa Midi bridge. 

Another question: How do I invoke the uninstall procedure for a program installed in Wine?
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how should we handle the Meltdown problem?

Safest is definitely to avoid connection to the internet.

Best is probably a sunshade by the pool and a nice cool beer. :-)
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AV Linux / Re: Kernel Page Table Isolation (aka Meltdown mitigation) - Please test!
« Last post by trulan on January 14, 2018, 06:05:15 PM »
Since I have an AMD FX cpu , should I test it , or it’s disabled by default on AMD CPUs ?
It's disabled on AMD cpus.  But feel free to test anyway, I would appreciate your feedback too.
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Since I have an AMD FX cpu , should I test it , or it’s disabled by default on AMD CPUs ?
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AV Linux / Re: Kernel Page Table Isolation (aka Meltdown mitigation)
« Last post by trulan on January 14, 2018, 03:06:57 PM »
Up for testing in the kernel repos is a new kernel: 4.14.12-rt10avl1.  Please thrash this one as hard as you can.  Test it thoroughly.

Please test this kernel with your default boot parameters, and also test it with adding "nopti" to the grub boot command.  Let us know if that makes any difference for you, and report what CPU you are using.  Moderately recent processors (~2011 and newer) have a feature (known as pcid) that should make kpti have less of a performance penalty.  My core2duo doesn't have pcid, so I might be seeing more of a performance penalty than most of you will.  But I might just stick with 4.14 kernels, given the fact that pcid is not supported on kernels older than 4.14.  And posts like this https://news.ycombinator.com/item?id=16087736 only add to my thinking that 4.14 is the way to go.

@GMaq, you'll need the "nopti" flag to boot this kernel in Virtualbox, at least until they fix VBox so it is compatible with kpti.

This kernel is currently only available in 64 bit. kpti is not available on 32 bit kernels as of this writing.  Maybe this is because the risk is less on 32 bit systems, maybe the fix is harder, or maybe nobody cares about 32 bit kernels anymore.  I haven't been able to figure out which it is.  Also, there's just an RT kernel for the moment, I will build a lowlatency variant after we get some more feedback on how this thing performs.

Thanks in advance for testing!
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AV Linux / Re: Kernel Page Table Isolation (aka Meltdown mitigation)
« Last post by GMaq on January 14, 2018, 10:59:42 AM »
Hi Trulan,

Thanks very much for all of your efforts on this and for the update, your time is very much appreciated!
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AV Linux / Kernel Page Table Isolation (aka Meltdown mitigation) - Please test!
« Last post by trulan on January 13, 2018, 01:20:04 PM »
Hi everybody,

The RT kernel sources have been updated to include the 'Meltdown' patches, officially known as Kernel Page Table Isolation, or kpti.  RT kernels v4.14 and v4.4 have been updated, though v4.9, which is what I have been working with, has not.  So, I've been testing v4.14.  My test setup is my trusty old core2duo, running a presonus firepod, or alternately the cheap built-in HDA intel soundcard.  For the firepod, I'm using the ffado drivers, not the new alsa firewire driver.

To start with, I was surprised to find just how low I could take the latency and still keep the audio stream stable.  Here are my (unscientific) test results with the firepod:

Ardour project, roughly ten tracks, a few effects.  96000 sampling.
Code: [Select]
Buffers:         pti enabled:       pti disabled:
64/3              stable             stable
64/2              mildly unstable    stable
32/3              unstable           mildly unstable
32/2              very unstable      very unstable       
As you can see, enabling kpti does have an observable impact.  Is it a 5 to 10% performance penalty? Probably.  But bear in mind that the latency difference between 64/3 and 64/2 is 0.66 ms (2 ms vs. 1.33 ms), and the internal round trip latency of the firepod (about 5 ms) is more than twice the total jack round trip latency.  It's still easily possibly, even on this rather aged computer, to be very stable with an actual round-trip latency of less than 10 ms.

I would expect that as you add effects, synths, and such, you'll continue to see a similar performance penalty.

My plan at this point is to include kpti in all future kernel builds.  You can add
Code: [Select]
noptito the grub command line to disable kpti, if you need the extra performance and don't need the security.

I'll post some kernels for you all to test in the next few days.
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Hi,

Is it better to ship with a 'lowlatency' default kernel with documentation to explain how to install an RT kernel if you want faster, lower latency Audio performance??

Please share your thoughts...
;)

I've been using AVL since 5.0.3 (currently 6.0.4) and using whatever kernel it ships with by default and have had no complaints. I'm using a Dell Vostro 1520 laptop. I think it has a hard-wired onboard video processor -- nothing very exciting.

Quote
pat@vostro:~$ uname -a
Linux vostro 3.12.19avl2-pae #4 SMP PREEMPT Mon Jun 16 22:55:48 EDT 2014 i686 GNU/Linux

pat@vostro:~/Downloads$ lspci  -v -s  $(lspci | grep ' VGA ' | cut -d" " -f 1)
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Dell Device 02bc
   Flags: bus master, fast devsel, latency 0, IRQ 48
   Memory at f6800000 (64-bit, non-prefetchable) [size=4M]
   Memory at d0000000 (64-bit, prefetchable) [size=256M]
   I/O ports at 1800 [size=8]
   Expansion ROM at <unassigned> [disabled]
   Capabilities: <access denied>
   Kernel driver in use: i915

'hope this helps!

I'm about to install the 2017 32-bit incantation because the browsers I have won't allow me to do my taxes. I'm hoping the more current browsers will work and, well, its been a few years anyway! I'll be on
the lookout for a 2018 edition.

Thanks for all your work on this awesome piece of software, Glenn!
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AV Linux / Re: Where is the program foloder in AV Linux?
« Last post by 33Nicolas on January 12, 2018, 06:05:37 PM »
Wow, thanks for that info.

It sounds as if for FF that I downloaded as Quantum was being introduced, I should just put it my home folder and do a launcher link from it. At least, I should do this until Debian makes FF 58 available in its package.

It's a little confusing, but it makes sense.
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HowTO's / Re: HowTO: AVLinux on UEFI
« Last post by GMaq on January 12, 2018, 03:09:11 PM »
Hi korakios!

Thank you SO much for sharing this!
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