snd-rtctimer module missing

[danmb]

The snd-rtctimer module is unavailable on both the generic and real-time Intrepid kernels.

The issue for me is that without this module, Rosegarden cannot use the RTC timer, and fails back on the imprecise (at 250 Hz) system timer. Not good for MIDI.

I have searched both Intrepid and Jaunty for snd-rtctimer.ko (from http://packages.ubuntu.com/) and it doesn't seem either of them include the module. In hardy, it used to be included in the linux-ubuntu-modules-* packages (which seems to be gone in Intrepid).

[Leann Ogasawara (leannogasawara)]

Thanks Dan. It seems CONFIG_SND_RTCTIMER would need to be enabled. Just adding information below for the kernel team to reference about the Kconfig option:

ogasawara@yoji:~/ubuntu-jaunty/sound/core$ grep -A15 "config SND_RTCTIMER" Kconfig

config SND_RTCTIMER

 tristate "RTC Timer support"

 depends on RTC

 select SND_TIMER

 help

   Say Y here to enable RTC timer support for ALSA. ALSA uses

   the RTC timer as a precise timing source and maps the RTC

   timer to ALSA's timer interface. The ALSA sequencer code also

   can use this timing source.

   To compile this driver as a module, choose M here: the module

   will be called snd-rtctimer.

   Note that this option is exclusive with the new RTC drivers

   (CONFIG_RTC_CLASS) since this requires the old API.

[danmb (danmbox)]

The doc says this is incompatible with CONFIG_RTC_CLASS. But in the Hardy config (e.g. /boot/config-2.6.24-23-generic) I see

CONFIG_RTC_CLASS=m

while in the Intrepid /boot/config-2.6.27-9-generic I see

CONFIG_RTC_CLASS=y

It seems that switching from built-in to a module would solve the incompatibility.

Another option is to use the new Alsa snd-hrtimer module at some point.

[Andy Whitcroft (apw)]

@Dan Muresan -- no even enabling RTC_CLASS will enable RTC_LIB and if that is != n then we are unable to enable the older legacy RTC option. The SND_RTCTIMER option is dependant on that being enabled. In short they really are incompatible. It does seem that this is also reported upstream in the kernel bugzilla which am linking from this bug.

    === driver/rtc/Kconfig ===
    config RTC_LIB
        tristate

    menuconfig RTC_CLASS
        tristate "Real Time Clock"
        default n
        depends on !S390
        select RTC_LIB
    [...]

    === drivers/char/Kconfig ===
    if RTC_LIB=n

    config RTC
    [...]

    === sound/core/Kconfig ===
    config SND_RTCTIMER
        tristate "RTC Timer support"
        depends on RTC

[Andy Whitcroft (apw)]

It appears that there will be a new hrtimers based timer source in 2.6.29, this appears to have merged to linus' tree and released in 2.6.29-rc1. So we should see this fixed in Jaunty+1 at a minumum.

[nardis_Miles1 (edwardsa)]

So, if we are running Jaunty (installed 06-14-09) we are out of luck for rtctimer or equivalent? This inhibits use of rosegarden.

[Paul Neaveill (boycotthell2005)]

To be honest, am not really in any shape to do upgrade at this point. Is there something we can do until we can do that upgrade? Fully agree on the rosegarden/ rtc issue.

[Alex Robinson (alex-launchpad-tranzoa)]

I have this problem, too, after moving from Hardy to Karmic. No RoseGarden.

Is there a work-around?

Tks.

[Kwinz (ldm)]

Confirmed with lucid.

kernel 2.6.32-22-generic
rosegarden 1:10.02-0ubuntu2

Rosegarden was unable to find a high resolution timing source for MIDI performance.

[Chris Metzler (cmetzler)]

Is there any update on a workaround to this?

Also, the link to the bug against the kernel upstream appears dead.

[danmb (danmbox)]

In newer kernels there is snd-hrtimer, which rosegarden can use as a timer source ("HR timer"). Your options are to upgrade to a new release (e.g. Lucid which is also LTS) or to custom-compile a 2.6.3x kernel for Hardy. I've actually done the latter before finally upgrading to Lucid.

[penalvch (penalvch)]

Dan Muresan, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/317120/comments/10 regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.

[dino99 (9d9)]

outdated flavor, report about a newer active version if needed