[mythtv-users] spontaneous reboots after upgrade & move to Ubuntu - IVTV/pre-emptive kernel locks?

Nedim Cholich mythtv at cholich.com
Sat Sep 8 01:35:02 UTC 2007

On 9/7/07, Peter Watkins <peterw at tux.org> wrote:
>  A couple weeks ago I upgraded my 0.19 system (based on Fedora Core 4 i386
> & Jarod's guide) to 0.20.x on Ubuntu 7.04 amd64, in preparation for
> Schedules Direct.
> The system has been spontaneously rebooting ever since -- uptime between 7
> minutes and 9 hours. Before this change, it was rock solid. Sometimes the
> HD3000/DVB tuner would fail (and record 0 bytes), but the hardware & OS were
> very stable. It /seems/ less stable when recording SD shows via IVTV and my
> PVR 500, but it /has/ successfully recorded some two hour movies, so it's
> not failing predictably.
> I've tried to test a number of components and came across the MythTV/IVTV
> wiki entry warning "Do *not* attempt to enable pre-emptive kernel locks in
> your kernel configuration--the ivtv modules do not get along with them and
> will cause *spontaneous reboots*." Is this possibly what I'm seeing? How
> can I tell: first, if my amd64 kernel supports pre-emptive kernel locks,
> and, second, if that's enabled? And can I disable them through /proc or a
> boot option?
> What has changed:
> I replaced two older ATA drives (replaced Seagate 200G and 250G with a
> matched pair of Seagate 500G), added a 1GB memory module (now has 2 GB RAM),
> and installed an additional 120mm case fan to help cool the drives & system.
> Instead of Fedora Code  4 i386 on /dev/hda I now have Ubuntu 7.04 amd64
> running on md raid (raid1 for /boot and /) -- which also means many upgraded
> software packages, including IVTV and NVidia drivers. I've replaced the 18
> month old Antec TruePower II 550w power supply with a new Sea Sonic 550w
> supply.
> Troubleshooting:
> The RAM checked out fine with an ~18 hour memtest86+ run. No errors have
> been reported on the drives by partitioning tools, SMART tools, etc. I've
> tried removing the new RAM, moving the RAM around and disconnecting the new
> case fan. I have disconnected a seldom-used SCSI tape drive and physically
> removed its host adapter. I switched SATA power cables for the SATA drives
> that I am still using. I have run StressCPU from UBCD for over three hours
> without trouble. I have not tried disconnecting either of the new 500G hard
> drives. The system temperature looks OK. There's no lm_sensors support, but
> when rebooting after normal use, the system temp is usually around 40 C and
> the CPU temp around 45 C. As stated above, I have replaced the power supply.
> I have run a 'cp' for a 4 GB file in a while [] loop to test the
> disk/md/lvm.
> Considering the previous stability, the new power supply, the success with
> memtest86+, and the results of my hardware tests, it seems very plausible
> that I'm having software trouble.
> System details:
> Athlon64 with 2 ATA and 2 SATA hard drives, using LVM atop "md" RAID1
> arrays for the MythTV recordings (MySQL data is on the simple raid1 md array
> for /). PS is a 550w Sea Sonic  S12, which gets AC through an APC UPS. Video
> is an Nvidia 6200 LE (AGP), feeding the TV via DVI, using the Nvidia binary
> driver (rev 9631, I believe -- the version suggested by Ubuntu's proprietary
> driver manager app, using NvAGP "2" for better picture quality). Three PCI
> cards: a pcHDTV HD3000 tuner used for ATSC, a Hauppauge PVR-500 used for
> SD/cable, and an old Ensoniq 1371 sound card. One DVD-RW on the second IDE
> channel, and, yes, a floppy drive. I'm running the Ubuntu kernel "
> 2.6.20-16-generic #2 SMP Thu Jun 7 19:00:28 UTC 2007 x86_64 GNU/Linux" and
> Ubuntu's IVTV 0.10.1. The config for that kernel (in /boot) has the
> following "preempt" kernel settings:
> # CONFIG_PREEMPT_NONE is not set
> # CONFIG_PREEMPT is not set
> Also, sometimes Ubuntu fails to boot, dropping me to a busybox prompt
> (looks like this problem, but the piix initramfs approach has not sufficed
> for me: https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/106864
> ; I haven't tried the quiet/splash/irqpoll boot settings yet). With the
> UPS, I'm not too worried about this; I only mention it in case someone
> thinks it relevant to the spontaneous reboots.
> Any help appreciated!
> -Peter

I feel your pain.

I can't tell if you're compiling your own kernel. If you are, don't do it.
Open the box, pull out all the cards and memory and put them back, making
sure all the cards are sitting nicely in their slots. Then install 32 bit
version of Ubuntu (64 bit is not really worth it, been there done that), and
don't do any customizations until you system stabilizes. Out of the box
Ubuntu 7.04 works with ivtv and mythtv great.

Keep the box opened and point a room fan at it to remove any possibility
that your problem is cooling related.

If it still crashes, start removing components, starting with HD3000. Give
the system enough time to crash in between and stop when it stops crashing.
Sometimes putting cards in different pci slots helps.

My current BE looks a lot like yours but instead of HD3000 I have HDHomeRun
(external, no pci issues), 1Gb ram and only one Seagate 500G drive. I
stopped doing all the lvm, raid/md funny stuff. Just plain XFS on a
dedicated tv disk. Recording and watching both SD/HD, system is rock solid.
I'm very careful about changes I make, always doing _one_ thing at the time,
giving enough time in between to see if the change destabilized it (usually
couple of days is good enough).

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