[PlanetCCRMA] sound card IRQ and crackling sound on F7

[Fernando Lopez-Lezcano]

On Tue, 2007-06-12 at 19:30 -0400, Hector Centeno wrote:
> Hi Fernando,
> 
> Thank you for your advice. It says the Audiophile has a latency of 64
> which is what it's set at in the BIOS. Should I reduce this?

The latency in this context is how many pci cycles can the card use
before it has to give up the bus. 

The point would be to see if there is another card that has that value
set very high and then can hog the pci bus itself and starve the
soundcard (64 sounds right for a default). 

-- Fernando


> On 6/12/07, Fernando Lopez-Lezcano <nando@ccrma.stanford.edu> wrote:
> > On Tue, 2007-06-12 at 16:56 -0400, Hector Centeno wrote:
> > > Hi,
> > >
> > > I'm having problems with my new motherboard (Asus P5B-VM with an Intel
> > > Core 2 Duo) and a M-Audio Audiphile PCI audio interface. My problem is
> > > mainly with Csound and getting crackling sound on one channel. If I
> > > set jack buffers to anything higher than 512x2 the crackling gets
> > > worse. I tried switching the card to the other PCI slot (it has only
> > > two) and the problem got even worse as I would get crackling audio
> > > always. I noticed that both PCI slots are sharing IRQ with other 3
> > > devices (usb, video card, libata). In the motherboards manual it says:
> > >
> > > 1.8.2 Configuring an expansion card
> > > After installing the expansion card, configure it by adjusting the
> > > software settings.
> > > 1. Turn on the system and change the necessary BIOS settings, if any. See
> > > Chapter 4 for information on BIOS setup.
> > > 2. Assign an IRQ to the card. Refer to the tables on the next page.
> > > 3. Install the software drivers for the expansion card.
> > >
> > > There is no more details about how to perform step 2, Chapter 4 only
> > > talks about reserving IRQ for ISA interfaces and in the bios there is
> > > no way to manually assign IRQs and it looks like it's something you
> > > are supposed to do va software, so I was wondering if anyone knows how
> > > to do IRQ assignment in Linux using the CCRMA kernel. With my older
> > > motherboard and FC6 it was possible to get the Audiophile to have it's
> > > own IRQ and I never had any problems with the audio (until the hard
> > > drive controllers in the mobo started to fail and had to replace it).
> >
> > I would check the pci latency settings just in case that's the problem.
> >
> > Do a "/sbin/lspci -v" and see what numbers you have for the latency
> > parameter for the cards installed (included the video card).
> >
> > -- Fernando
> >
> >
> >
> 
>