[mythtv-users] DVB(S) tuner sensitivity (and my other) experiences
RobertCL at iname.com
Sun Feb 18 16:38:11 UTC 2007
> > Swapping slots isn't an option as both PCI slots are used and the
> > graphics card is AGP. And yes, the Quadro is only supported by the
> > legacy NVidia drivers, but the version number isn't that far behind
> > the latest drivers. (The card was given to me which is why I'm using
> That's the issue with SFF pc's. Lack of space to juggle cards around. I
> wish in hindsight i'd gone for a bigger media htpc case.
Indeed. I would certainly buy a "larger" case next time, to have room
for capture cards, etc, but since I got the offer of a P4-2.66 in a
fairly quiet SFF case for £30 I thought it was worth a shot for my first
> >> I have, CPU usage is generally low (10%) when recording DVB-S and
> >> doesn't max out at any point.
> > How do you check interrupt usage with vmstat? Is this just the IO
> > column?
> No the 'in' column (as in 'interrupts') from vmstat.
Ah, of course. It seems to be usually around 1400 during recording /
playback and I've not see it go much above that. I don't know if this
is good or bad!
> When you have the nv/agpgart driver loaded as oposed to the nvidia i'm
> sure it's not on the same IRQ 16 as your DVB card is it?
Indeed. The nv driver doesn't seem to use any interrupts as far as I
I've tried noapic and irqpoll, but neither fix the problem. noapic
seems to make it a little better, but that could just be subjective.
The annoying thing is that one of my DVB-S channels doesn't have this
problem at all under linux. And they all work fine when I use Windows
on the same box. Also my STB which is connected to the same feed from
the sat dish works flawlessly on all channels.
I think I might look into getting a new graphics card and see if that
helps matters, but I keep thinking if it works under Windows then why
not under Linux?
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