[mythtv-users] Re: Nova-T ac-tex damaged etc.

[Scammell, David]

UDMA was the problem. Pci=noacpi on the command line cured my DMA problems,
I now get 55M/s from the drive and it basically records with no issue.

I couldn't persuade the 2.6 kernel linuxtv driver to work yet, seems like
others on that mailing list also couldn't get it to work. 2.4 seems good
though.

I still see some errors from the backend but I'm putting this down to poor
reception, mostly its top notch.

I get backend failures from time to time, say once a day but I'm putting
this down to incorrectly specified channel parameters/CVS version and can
live with for now.

I'm a happy bunny now I've got the server and the xbox frontend+remote
working, still playing with it all.

Cheers for the help.

David Scammell


-----Original Message-----
From: Martin Brown [mailto:Martin.Brown at macquarie.com] 
Sent: 21 December 2003 22:52
To: Scammell, David
Subject: Re: [mythtv-users] Re: Nova-T ac-tex damaged etc.


David,

My disk throughput went from about 5M/s to 50M/s (non cached - cached was
about 500M/s) so I'm guessing that 10M/s would probably cause you problems.
I don't think that using dvbstream piped straight to xine does an
intermediate disk dump so that worked fine for me.

Martin

Scammell, David wrote:
> Martin,
> 
> I'm seeing this, the errors appear to kill the backend as well.
> 
> I've got a UDMA 133 drive (MAXTOR 7Y250P0), running at UDMA 100, UDMA 
> support is compiled in (sis5513-sis735) and (appears) is auto 
> activated by the kernel. Unmasking interrupts didn't really make any 
> difference to the transfer rate, ~10MB/s.
> 
> I suspect this motherboard supports UDMA 133 transfers but this 
> kernel, vanilla 2.4.22 inc dvb support doesn't grok it. I think I will 
> have to look for a bios upgrade, then possibly tweak the sis driver to 
> understand it. Name of the motherboard is not to hand though right 
> now.
> 
> Should I see <much> better throughput than this?
> 
> I'm surprised that the UDMA configuration of the machine causes so 
> such an issue, the bandwidth needed to disk from the nova-T shouldn't 
> be so much, even with a slightly mis-configured disk. I'll have to try 
> dvbsteam again, it did stream data perfectly to disk before, no 
> significant errors. Why should it have such a problem when Mythtv is 
> in charge?
> 
> I think getting the correct channel info of Freeview from xmltv will 
> be the next challenge!
> 
> David Scammell
> Unix System Administrator
> Global Tech. OPS (Chichester)
> Mercer HRC - Extension 22525
> +44 (0)1243 522525 Desk
> +44 (0)7789 030182 Mobile
> 
> 
> 
> -----Original Message-----
> From: Martin Brown [mailto:Martin.Brown at macquarie.com]
> Sent: 16 December 2003 21:31
> To: mythtv-users at mythtv.org
> Subject: [mythtv-users] Re: Nova-T ac-tex damaged etc.
> 
> 
> Just to let people know who might have the same problem that I had: 
> large scale quantisation break up, streaming "ac-tex damage" errors, 
> etc.:
> 
> Check that DMA is enabled on the disk storing the Myth data. I had to 
> recompile my kernel with support for my IDE controller before I could 
> do this, but then turning DMA on with hdparm boosed the
> disk speed 10 fold and got rid of the errors I was seeing.
> 
> Thanks to those who responded to my quenstions.
> 
> Now on to the next challenge...
> 
> Martin Brown
> 
> 
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