ACPI and IEEE1394

ACPI and IEEE1394

Not sure if this is the time or place to ask this, and I may be well out of my depth here, but I am trying to find some guidance on the following....

Like many of my contacts, I have been trying to sort out problems with power management on machines that use 1394 to control audio devices. The basic problem is intermittent operation of the 1394 connection. The normal advice on the internet is for people with problems to reconfigure the PC as a "Standard PC", ie not use ACPI.

I have been testing using two machines, both rather old - an IBM TP R40 (1.3GHz Pentium M) and Acer 292 (1.5GHz Pentium M). These have built-in 1394, and I have tested the same machines with 5 separate IEEE 1394 pcmcia cards, all of which provide similar results. At the same time, 2 desktop machines work flawlessly with the same audio hardware. The audio device in my case is a Tascam FW-1884, which aiui uses both isochronous and asynchronous 1394 communication.

The failure I am experiencing is that after a random period of time the audio fails from the PC to the audio device, but audio still passes from the device into the PC. This looks as if the firewire audio settings are dropping to a different state. At the time of failure the hardware control of the audio device also fails.

It appears as though if I set the Power Management to "Always ON", the problem is much reduced or disappears completely. If I then bring the Power management back into operation, the problem doesn't return until I reboot the PC.

I appreciate that this is rather obscure and that my hardware is not current, but wonder whether anyone can offer any advice on how to proceed.

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Have to make a correction to the above in the unlikely event that anyone is interested.

The 1394 audio does actually still pass in both directions (I had misunderstood the Tascam interface). Thus the problem seems to be that the isochronous transfer is maintained, but the asynchronous data transfer fails at a random time.

Thank you for posting to the Intel Software Network Forum.

Your ACPI and IEEE1394 question is outside the scope of this forum. Your design inquiry will require a closer look by an Intel Product Representative.

If your company has its own Intel representative, you may wish to inquire whether they are able to assist with this inquiry. Your company's Purchasing Department will normally have your Intel representative's contact information. If you have no contact, please see under "Design Components".

If your location is not listed, please see an Intel Authorized Distributor and ask for a Field Application Engineer (FAE). Our Intel Authorized Distributor list is also linked from the URL above.

Best regards,
Jim A
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I have a very similar problem with an 865PE chipset with built-in IEEE 1394. I just got an external firewire DVD drive. It works fine and shows up in the File Explorer with a drive letter but then after an intermittent amount of time it goes away and is listed with a yellow exclamation mark in Device Manager. XP loaded the drivers for the chipset and I was wondering if I should use the Intel chipset drivers for this M/B? Maybe its an ACPI problem like the previous post? Maybe the firmware on the DVD interface (external box) is causing this? Its driving me crazy. I always have to restart to get it to be recognized again.

We're locking this thread -- as Jim mentioned above, these forums are geared toward software development topics.

For end-user chipset support, please submit issues to Intel Customer Support using their email form located here, or visit for FAQs.

For hardware design issues, please refer to the information Jim posted upthread.


Lexi S.

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