Ralf, Keep making these type postings; we need your expertise and questions! Ken
On Sun, Jul 11, 2010 at 8:29 PM, Ralf Mardorf <ralf.mard...@alice-dsl.net>wrote: > Hi :) > > I'm new to the list. Regarding to hw MIDI jitter, I'm testing and > comparing several Linux setups. > > Here is a rough summary of my latest thread on LAD. > > I wonder what I need to do, to get a kernel-rt for Ubuntustudio 10.04? > > ........................................................................ > Ubuntu Studio 10.04 amd64 > $ uname -a > Linux ubuntu 2.6.32-23-preempt #37-Ubuntu SMP PREEMPT Fri Jun 11 > 10:19:07 UTC 2010 x86_64 GNU/Linux > > $ alsa-midi-latency-test -Rrw=2 -o20:0 -i20:0 > > alsa-midi-latency-test 0.0.3 > > set_realtime_priority(SCHED_FIFO, 99).. done. > > clock resolution: 0.000000001 s > > SUCCESS > > best latency was 1.00 ms > worst latency was 3.36 ms, which is great. > > 3.36 ms isn't great, but unusable to make music. > > ........................................................................ > openSUSE 11.2 amd64 > > uname -a > Linux suse11-2 2.6.31.6-rt19 #1 SMP PREEMPT RT Wed Nov 18 16:59:26 CET > 2009 x86_64 x86_64 x86_64 GNU/Linux > > > alsa-midi-latency-test -Rrw=2 -o16:0 -i16:0 > > alsa-midi-latency-test 0.0.3 > > set_realtime_priority(SCHED_FIFO, 99).. done. > > clock resolution: 0.000000001 s > > SUCCESS > > best latency was 0.99 ms > worst latency was 1.05 ms, which is great. > > ........................................................................ > > PREEMPT vs PREEMPT RT and of course frequency scaling for an audio > distro should be at performance by default, anyway, the frequency > scaling isn't a big deal. > > I tried to boot the kernel-rt from the Ubuntu repositories and I tried > to build a kernel-rt myself. > > If I try to boot kernel 2.6.31-11-rt or kernel 2.6.31-10-rt from the > repositories I get > 'mount: mounting none on /dev failed: No such device.' Regading to the > web this might be, because of CONFIG_DEVTMPFS. > > # cat config-2.6.31-11-rt | grep CONFIG_DEVTMPFS > # cat config-2.6.32-23-preempt | grep CONFIG_DEVTMPFS > CONFIG_DEVTMPFS=y > CONFIG_DEVTMPFS_MOUNT=y > > 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'. > > At least this three kernel-rt from the repositories come with an initrd. > The kernel I tried to build the way I usually build kernels for Ubuntu > with success, is missing an initrd. > > $ 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)' > > Any hints are welcome! > > Cheers! > > Ralf > > > -- > Ubuntu-Studio-users mailing list > Ubuntu-Studio-users@lists.ubuntu.com > Modify settings or unsubscribe at: > https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-users >
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