in search for the /boot/config-...... file

[pelgrim]

running Ubuntu

In order to start working with midi signals, I follow this guide
http://tedfelix.com/linux/linux-midi.html

Under the title: Installing a Low Latency Kernel
I need to change the kernel config file:

Code:

$ grep ^CONFIG_HZ /boot/config-`uname -r`
CONFIG_HZ_1000=y
CONFIG_HZ=1000

in the /boot directory I can not find any config file.
Where can I do this ?

[martinayotte]

This is related to kernel build config, therefore you would need to compile your own kernel.
The current value in longsleep builds is CONFIG_HZ=100 and no define for CONFIG_HZ_1000.

[pelgrim]

does that mean I can't use my pine64 for midi recording ?

[dkryder]

if kernel does not include PREEMPT try this,
$ sudo apt-get install linux-lowlatency
not sure if that will fix it in ubuntu, but your goal is to have a low latency kernel
also, you should start reading about kernels and this fellows guide. perhaps sending him emails will help.
but he did mention this,
Note: Ubuntu/Debian can set up a properly configured audio group for you when you install jackd2. If you'd like, you can do this before continuing:

$ sudo apt-get install jackd2

have you done that yet?

[pelgrim]

I have executed all until the lowlatency part, including the jackd2.

Since the kernel does include PREEMPT, I didn't install the linux-lowlatency package.
But you're right, I should give it a try, nothing to loose but time.

---

just tried:

unable to locate package linux-lowlatency.

[dkryder]

if the kernel includes the PREEMPT then according to the guide it is a low latency. so no need for the package. also you should have a workable kernel. just carry on with next step.
also, this guy should host a forum or at least have a mail list but i did only see this,
http://tedfelix.com/email.html
probably best to contact him going forward. good luck and let us know how it works.
you might find current setting in /usr/src/linux-headers*/.config but to change a re-compile, as mentioned by martinayotte, would be needed

[martinayotte]

In longsleep kernel build the flag CONFIG_PREEMPT seems to be there :

CONFIG_TREE_PREEMPT_RCU=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT_NOTIFIERS=y
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_DEBUG_PREEMPT=y
# CONFIG_PREEMPT_TRACER is not set

[pelgrim]

I'm indeed moving on now ignoring this setting,
trying to sort things out in another thread to load the snd_seq module in the kernel

[longsleep]

# CONFIG_SND_SEQUENCER is not set

You need to build your own Kernel for that for now. Create a PR on GitHub if you want it to be enabled in my builds.

[longsleep]

I just released Kernel 3.10.101-4-pine64-longsleep-51 which has the sound sequencer.