[LAU] irq sharing
gnome at hawaii.rr.com
Thu Aug 26 19:45:05 UTC 2010
Mark Knecht wrote:
> On Thu, Aug 26, 2010 at 2:08 AM, david <gnome at hawaii.rr.com> wrote:
>> David Santamauro wrote:
>>> On Tue, 24 Aug 2010 12:46:06 -0700
>>> Niels Mayer <nielsmayer at gmail.com> wrote:
>>>> On Tue, Aug 24, 2010 at 8:13 AM, David Santamauro <
>>>> david.santamauro at gmail.com> wrote:
>>>>> thanks for the time. I only have one PCI slot, but 3 empty PCI-x
>>>>> I basically unplugged all USB devices as well as shut off both
>>>>> network interfaces and on board audio interface in the bios and the
>>>>> noise persists ...
>>>>> Not sure what to try next, this was a shot-in-the-dark.
>>>> If you think it's a interrupt-sharing issue, consider using a
>>>> pcie-to-pci riser to plug in your card. Apparently, this way of doing
>>>> things may ensure less bus contention:
>>>> Also, be sure that interrupt contention is really the problem. If
>>>> it's a constant noise, there's a better chance that it's a different
>>>> problem. One issue is that your recording software may not be using
>>>> the same bit depth, alignment, or complement as what the card
>>>> expects. I can get this effect on output, for example, simply by
>>>> using 'mplayer'
>>> interesting angle ...
>>> envy24control (and the new mudita24) register this noise on input
>>> whether devices are plugged in or not. So the noise is clearly coming
>>> from either the delta breakout, card or driver. I've ruled out the
>>> breakout box and card simply by the fact that the noise doesn't exist
>>> on the same hardware with windows7 drivers.
>> Or the Windows drivers are doing something that removes the noise?
>> I have a friend who has a Delta 1010LT in his WindowsXP-based audio
>> workstation. He's never said anything about input noise.
> That would imply that everyone using a 1010LT in Linux would
> experience the same noise, correct?
> If I understand, you are saying that the card, with nothing plugged
> into it, shows noise coming out of the card? If so it sounds like a
> bad card.
Oh, I'm not the original poster. Although that could be something the
original poster might try. IIRC, he mentioned that the noise isn't there
under Windows7 or 32-bit Linux. Only 64-bit Linux.
> If he's local can you ask your Windows friend to plug your card into
> his system for testing and see if it's noisy or not? Good weekend
> project if he's game.
That's worth checking.
Another a idea for original poster: Boot your existing hardware from a
live Linux audio distro such as Ubuntu Studio or Musix or ArtistX or
some such, and see if the noise exists. Just in case it's some obscure
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