[LAD] PCI MIDI jitter - comparison Ubuntu (bad) and Suse (might be ok)

[Ralf Mardorf]

On Sun, 2010-07-11 at 12:02 -0700, Niels Mayer wrote:
> It's perfectly fine for the 1712, and the audio sync probably has
> nothing to do with midi jitter.

Yep, I just wanted to underline that at the moment this are two cards,
but one virtual.

Unfortunately no kernel-rt is boot-able for my Ubuntu Studio 10.04. If
64 Studio isn't continued, I don't know any good DEB based audio Linux
for 64-bit architecture. AV Linux seems to be good, but is released only
as i386.

Hm, perhaps OT for this list:

I wonder if anybody run Ubuntustudio 10.04 with a kernel-rt.
Building a kernel failed.
And all kernel-rt from the repositories failed.

$ cd /usr/src
$ sudo synaptic
  I checked if those packages were installed:
  bin86
  build-essential
  bzip2
  fakeroot
  gcc
  kernel-package
  make
  libncurses5-dev
$ wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.33.5.tar.bz2
$ wget
http://www.kernel.org/pub/linux/kernel/projects/rt/patch-2.6.33.5-rt23.bz2
$ tar xvjf linux-2.6.33.5.tar.bz2
$ rm linux-2.6.33.5.tar.bz2
$ mv linux-2.6.33.5 linux-2.6.33.5-rt23
$ ln -s linux-2.6.33.5-rt23 linux
$ cd linux
$ bunzip2 ../patch-2.6.33.5-rt23.bz2
$ patch -p1 < ../patch-2.6.33.5-rt23
$ rm ../patch-2.6.33.5-rt23
$ cp /boot/config-2.6.32-23-preempt .config
$ make oldconfig
  81 x Enter
$ make menuconfig
  Edited from Generic-x86-64 to Opteron/Athlon64/Hammer/K8
  Save an Alternate Configuration File
$ make oldconfig
  Nothing to do
$ make-kpkg clean
$ export CONCURRENCY_LEVEL=2
  This didn't work:
  $ make-kpkg --rootcmd fakeroot --initrd kernel-image kernel-headers
kernel-source
    50 minutes later
    make[5]: *** [drivers/staging/comedi/drivers/quatech_daqp_cs.o]
Error 1
    make[4]: *** [drivers/staging/comedi/drivers] Error 2
    Hence I edited .config:
    $ cat .config | grep COMEDI
      CONFIG_COMEDI=m
      # CONFIG_COMEDI_DEBUG is not set
      CONFIG_COMEDI_PCI_DRIVERS=m
      CONFIG_COMEDI_PCMCIA_DRIVERS=m
      CONFIG_COMEDI_USB_DRIVERS=m
    $ gedit .config
    $ cat .config | grep COMEDI
      # CONFIG_COMEDI is not set
      # CONFIG_COMEDI_DEBUG is not set
      # CONFIG_COMEDI_PCI_DRIVERS is not set
      # CONFIG_COMEDI_PCMCIA_DRIVERS is not set
      # CONFIG_COMEDI_USB_DRIVERS is not set
    $ make oldconfig
      Nothing to do
    $ make-kpkg clean
  $ make-kpkg --rootcmd fakeroot --initrd kernel-image kernel-headers
kernel-source
    Another 50 minutes later
    make[4]: *** [drivers/staging/pohmelfs/inode.o] Error 1
    make[3]: *** [drivers/staging/pohmelfs] Error 2
    Hence I edited .config:
    $ cat .config | grep POHMEL
      CONFIG_POHMELFS=m
      # CONFIG_POHMELFS_DEBUG is not set
      CONFIG_POHMELFS_CRYPTO=y
    $ gedit .config
    $ cat .config | grep POHMEL
      # CONFIG_POHMELFS is not set
      # CONFIG_POHMELFS_DEBUG is not set
      # CONFIG_POHMELFS_CRYPTO is not set
    $ make oldconfig
      Nothing to do
    $ make-kpkg clean
Here it is ok:
$ make-kpkg --rootcmd fakeroot --initrd kernel-image kernel-headers
kernel-source
      80 minutes later
$ cd ..
$ sudo dpkg -i
linux-image-2.6.33.5-rt23_2.6.33.5-rt23-10.00.Custom_amd64.deb

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

When I tried to boot the kernel I got

'[    0.499322] ACPI: Expecting a [Reference] package element, found
type 0
 [    0.811991] kernel panic - not syncing: VPS: Unable to mount root fs
on unknown-block (0,0)'

For the entry in grub.cfg initrd is missing:

menuentry 'Ubuntu, with Linux 2.6.33.5-rt23' --class ubuntu --class
gnu-linux --class gnu --class os {
	recordfail
	insmod ext2
	set root='(hd1,11)'
	search --no-floppy --fs-uuid --set 54b5bb8c-356a-4268-8592-e76aac7941a8
	linux	/boot/vmlinuz-2.6.33.5-rt23 root=/dev/sdb11 ro   quiet splash
}

Unfortunately initrd is missing too:

$ ls /boot/initrd*
/boot/initrd.img-2.6.32-23-preempt
$ ls /boot
abi-2.6.32-23-preempt     grub
System.map-2.6.32-23-preempt  vmlinuz-2.6.32-23-preempt
config-2.6.32-23-preempt  initrd.img-2.6.32-23-preempt
System.map-2.6.33.5-rt23      vmlinuz-2.6.33.5-rt23
config-2.6.33.5-rt23      memtest86+.bin

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

'Kernels

* Amd64
-generic will be installed if ubuntustudio-audio meta is NOT selected
during installation process
-preempt kernel will be installed if ubuntustudo-audio meta IS selected
during installation process
-lowlatency kernel is also available in Abogani's PPA -
https://launchpad.net/~abogani/+archive/ppa
-realtime kernel will be available in Ubuntu Studio PPA'
http://ubuntustudio.org/LucidLynx

So I added 'deb http://ppa.launchpad.net/abogani/ppa/ubuntu lucid main'
and
'deb-src http://ppa.launchpad.net/abogani/ppa/ubuntu lucid main'. Then I
installed the rt kernel from this repository.

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

When I try to boot kernel 2.6.33-23-realtime from the repository I get
'ACPI: Expecting a [Reference] package element, found type 0' too, but
no kernel panic, instead it will boot into text mode.

Cheers!

Ralf