[mythtv-users] A7N8X-E Deluxe Stability with HD2000 / FBUS, FDSR, IRQ Lockup

Mike Isely isely at isely.net
Tue Nov 29 15:05:31 EST 2005

On Mon, 28 Nov 2005, John Freer wrote:

> Hi All,
> Looking for suggestions on which way to go.
> Background:
> I've got an XP2600, 333FSB, in an Asus A7N8X-E Deluxe motherboard
> with a MX440 at 8x AGP.  As tuners, I've got a PVR-250, HD-2000
> (dvb-bt8xx DVB Driver), and a Win-TV dbx (software btttv card).

I have a system set up using this motherboard with an XP3200 / 444FSB. 
The video card is an nvidia FX5200 based device.  This system does not 
currently run MythTV, but read on...

> Assuming nothing else is going on, I can playback 1080i content with
> ~5% free.

I have an HD-3000 which I've tried there a few times (not using MythTV). 
Recording from it is not a problem, but playback of 1080i exacts a heavy 
toll using mplayer.  I seem to use 60-75% of the CPU doing the decoding, 
with the "xv" mplayer backend (which should be using hardware scaling on 
the video card).

> I'm running FC3 with 2.6.12 / 18.1 mythtv.  All dist-upgraded to the
> latest at-testing.

My System is debian based, with various kernels over time.  Last time I 
tried the HD-3000 there I was running 2.6.10 (using a ported version of 
the pcHDTV driver before it got into dvb).  I'm currently running this 
board with and I've test driven 2.6.15-rc2 on it.

> Other HW installed is 2x IDE HDD's, Linksys WLAN NIC.  Using onboard
> sound, ethernet.

Similar here...

> Symptoms:


I don't see any of those symptoms, but then I'm not running MythTV.

However the whole reason why I'm even posting this message is because of 
all the motherboards I have dealt with over the years, this ASUS A7N8X-E 
has been the most unstable piece of crap I've ever encountered since back 
in the bad of old of cruddy '486 boards.  When I first put this system 
together it wouldn't run more than a few hours before wedging hard.  That 
was back in 2.6.5 days.  Since that time I've done various strategies to 
resolve this stability issue, but after 1.5 years it still isn't perfectly 
stable.  I've swapped power supplies, tweaked BIOS settings, implemented 
some custom kernel hacks (this board had a known problem apparently 2 
years ago that screwed up interrupt handling in Linux), and I've even 
burned in the memory for days at a time with memtest86 without a single 
glitch.  These days the system still wedges about once every 3-4 weeks. 
Sure that's no problem for a workstation, but that makes it totally 
unsuitable for a server environment (like MythTV) which must remain up 
24x7.  The system does not run hot at all.

I have put together a lot of systems over about 17 years; this one I think 
I've just come to accept will never be perfectly stable.  It just seems to 
be lousy.  For example - don't disable LPT1 in the BIOS because the system 
will otherwise generate spurious IRQ7's which of course get shut down in 
Linux (as it must be), wrecking access for any devices which attempt to 
share that interrupt.  I could go on and on, but I just don't trust this 
board at all.

I recommend you replace the mainboard.


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