[mythtv-users] Lots of DVB continuity errors???

[Chris Birkinshaw]

>
>>
>>Does anyone else have this problem? I'm sure it's not related to
>>resources, since the disk being
>>used as a buffer shows read speeds of 50MB/sec using "hdparm -t /dev/md1",
>>and the system is
>>running with an 800Mhz Duron with 768MB RAM. Does anyone know if mythtv
>>has implemented the DVB
>>inner and outer coding error correction, or if it just relies on the error
>>correction within the
>>MPEG stream?
>
> Have you checked dmesg for DMA errors? Your hard drive might well be very
> fast, but if DMA on the PCI (as opposed to the IDE) bus is dodgy, you'll
> get breaks in the stream. Some chipsets have known issues in Linux that you
> don't get under windows (closed source drivers), most notably the VIAKT133
> and 266 IIRC.
>
> If you think it is Myth's fault, try watching the DVB stream in Xine and
> see if the same error occurs.
>
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>

I know that my motherboard has a VIA pro chipset... this is starting to sound like it may be the
problem :-(

Running dmesg just gives loads of firewall messages, but running grep for DMA in /var/log/messages
returns:

Jun 28 00:09:22 postbox kernel:   DMA zone: 4096 pages, LIFO batch:1
Jun 28 00:09:27 postbox kernel: VP_IDE: VIA vt82c686b (rev 40) IDE UDMA100 controller on
pci0000:00:07.1
Jun 28 00:09:27 postbox kernel:     ide0: BM-DMA at 0xc000-0xc007, BIOS settings: hda:DMA, hdb:DMA
Jun 28 00:09:27 postbox kernel:     ide1: BM-DMA at 0xc008-0xc00f, BIOS settings: hdc:DMA, hdd:DMA
Jun 28 00:09:27 postbox kernel: PDC20267: (U)DMA Burst Bit ENABLED Primary PCI Mode Secondary PCI
Mode.
Jun 28 00:09:27 postbox kernel:     ide2: BM-DMA at 0xe400-0xe407, BIOS settings: hde:pio, hdf:pio
Jun 28 00:09:27 postbox kernel:     ide3: BM-DMA at 0xe408-0xe40f, BIOS settings: hdg:pio, hdh:pio
Jun 28 00:09:28 postbox kernel: hda: 19941264 sectors (10209 MB) w/2048KiB Cache, CHS=19783/16/63,
UDMA(66)
Jun 28 00:09:28 postbox kernel: hdb: 117231408 sectors (60022 MB) w/2048KiB Cache,
CHS=16383/255/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hdc: 120103200 sectors (61492 MB) w/1821KiB Cache,
CHS=16383/255/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hdd: 160086528 sectors (81964 MB) w/2048KiB Cache,
CHS=65535/16/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hde: 120103200 sectors (61492 MB) w/1821KiB Cache,
CHS=16383/255/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hdf: 120103200 sectors (61492 MB) w/1821KiB Cache,
CHS=16383/255/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hdg: 120103199 sectors (61492 MB) w/1863KiB Cache,
CHS=65535/16/63, UDMA(100)
Jun 28 00:09:28 postbox kernel: hdh: 117231408 sectors (60022 MB) w/2048KiB Cache,
CHS=16383/255/63, UDMA(100)


This doesn't seem to show any problems, is there anywhere else I could look?

Thanks for your help so far,

Chris