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#1019 System timer res. msg. always displayed? Do have 1KHz, rtc

closed
Chris Cannam
sequencer (64)
9
2012-09-16
2006-12-05
Hans Voss
No

I compile Rosegarden 1.4.0 on my customized Slackware 10.2 Linux laptop.

I got the System timer Resolution msgbox and immediately knew that my kernel timing was off (I had some thought about wanting the default 250 or upgrading to 1000 when building the kernel).

I changed to 1KHz but the msgbox still appears
I forced rosegarden to use the RTC timer and the box still appears.

I use kernel version 2.6.17.13
snd_rtctimer is in the lsmod list
I have the following two lines in my kernel config
CONFIG_HZ_1000=y
CONFIG_HZ=1000

I had the Rosegarden configuration for Sequencer->Synchronisation on all three off:
Auto
system-timer
* rtc

And in all situations I get the dialog box "System timer resolution too low..."

Discussion

  • Chris Cannam
    Chris Cannam
    2006-12-05

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    What is the contents of /proc/asound/seq/timer when Rosegarden is running, for each of the three synchronisation settings?

     
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    Contents of /proc/asound/seq/timer

    With rosegarden set to: system timer:
    Timer for queue 0 : system timer
    Period time : 0.004000000
    Skew : 65536 / 65536

    With rosegarden set to: rtc
    Timer for queue 0 : RTC timer
    Period time : 0.000976562
    Skew : 65536 / 65536

    With rosegarden set to: auto
    Timer for queue 0 : system timer
    Period time : 0.004000000
    Skew : 65536 / 65536

    And, just for good measure the contents of /proc/cpuinfo:
    processor : 0
    vendor_id : GenuineIntel
    cpu family : 6
    model : 9
    model name : Intel(R) Pentium(R) M processor 1500MHz
    stepping : 5
    cpu MHz : 1500.000
    cache size : 1024 KB
    fdiv_bug : no
    hlt_bug : no
    f00f_bug : no
    coma_bug : no
    fpu : yes
    fpu_exception : yes
    cpuid level : 2
    wp : yes
    flags : fpu vme de pse tsc msr mce cx8 sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 tm pbe up est tm2
    bogomips : 2991.94

     
  • Chris Cannam
    Chris Cannam
    2006-12-05

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    Looks like you do still have the 250Hz system timer -- as the period for this timer is reported (by the kernel) as 0.004, that is 1/250 seconds.

    Rosegarden is therefore right to show you the warning if you have the timing source set to "System Timer", and it will also do so if you have it set to "(auto)" because RG doesn't try to use the RTC timer when you have "(auto)" selected (it has caused system hangs with some kernel versions).

    However, if you set the RG timing source to RTC and still get the warning dialog, then that is a bug in RG.

     
  • Hans Voss
    Hans Voss
    2006-12-05

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    I still get the message when RTC is selected. (Not immediately after selecting it which is the case with auto) but at the next time I start Rosegarden.

    BTW: is there another way (not /proc/asound/seq/timer) for me to check on the timer frequency (that you guys know of) That would enable me to check if my kernel config actually works.

     
  • Chris Cannam
    Chris Cannam
    2006-12-05

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    Will investigate the message reporting when RTC is selected.

    Besides "zcat /proc/config.gz | grep HZ" (if you have config reporting switched on in the kernel), I'm not sure how else you'd query the Hz setting.

    /proc/asound/seq/timer reports the timing resolution that Rosegarden is actually able to use (as provided by the kernel sequencer API), so if that is reporting 250Hz, there is nothing Rosegarden or any other ALSA sequencer based userspace process can do about it besides selecting a different timing source (such as RTC).

    FWIW it seems that the RTC setting should work fine for you, apart from the warning.

     
  • Hans Voss
    Hans Voss
    2006-12-05

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    Thanks so far,

    Perhaps an option to switch off the message (do not show this message again)?

    Even on the (apparently 250Hz) system timer it works well (enough).
    I had attributed the 'lag' I had between display and sound to fluidsynth.

     
  • Hans Voss
    Hans Voss
    2006-12-05

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    Hmmm,

    The zcat /proc/config.gz | grep HZ also reports
    CONFIG_HZ_1000=y
    CONFIG_HZ=1000

    A problem with alsa maybe? Oh well.

     
  • Chris Cannam
    Chris Cannam
    2007-10-09

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    Should (finally) be fixed in SVN rev 8291

     
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