jekagan
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High DPC latency from ACPI.sys on Latitude 7389 causing audio glitches

I'm presently trying to chase down a DPC latency issue with a Latitude 7389 2-in-1 that is causing random glitches while trying to process real-time audio, both with the built-in Realtek audio and with 3 other external USB audio interfaces.

Having gone through all the usual suspects, I still get high DPC latency from ACPI.sys as reported by LatencyMon.  This is even with the ACPI battery and the WiFi adapter disabled in Device Manager.  The power profile is configured to be as high performance as allowable.  All the USB devices have "Allow the computer to put this to device to sleep... blah blah blah" unchecked.

http://www.resplendence.com/latencymon

OS is Windows 10 Fall Creators Update.  I just tried the April update today and it was even worse.

The maddening thing is that I have three older Dell laptops (Inspiron M731R, Inspiron 3521, Venue 11 Pro 7130) that ALL outperform this 7389 in terms of the DPC latency.  I'm at wit's end with this machine.  Dell support has opened a ticket but has yet to provide any real solution.

Has anybody experienced anything similar or found any solutions?

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12 Replies
jekagan
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing audio glitches

And before anyone asks, all the drivers are latest.

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MsT49
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Re: High DPC latency from ACPI.sys on Latitude 7389 causing audio glitches

I rolled back to the Windows generic driver instead of the Realtek driver (Dell 7389), because the Realtek driver seemed to not work well at times (no sound on Netflix at times; issues with switching to headphones etc).

These problems I had are probably unrelated to your issue however, given what you've written.

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jekagan
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing audio glitches

It doesn't matter if I use the onboard audio or an external USB audio interface.  Sooner or later the DPC latency will cause an audio glitch, which makes the laptop unsuitable for live performance situations where audio clicks and pops are unacceptable.  The issue has nothing to do with the specific audio interface.  It's another driver and/or the BIOS that is taking WAY too long to process interrupts.

Simple math:

Processing audio at 48KHz with a 128 sample buffer means the audio buffer has to be filled every 2.67 milliseconds. Depending on the complexity of the audio processing, when another thread on the system hogs the CPU for 1ms+ consistently and occasionally 2ms+ then sooner or later one of those buffers will not be processed within less than 3ms.  Click.  Pop.

It's shameful that a 4-year-old i3 that cost half as much can do this, and yet the 7389 cannot.

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the.rem
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

Hi, any updated info on this topic? There seems to be slient legions of audio users facing he same problem, myself included

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jekagan
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

Short answer: no.

The support rep who was handling my case basically said the engineers weren't going to hunt this down.

I ended up returning the machine to Dell and buying a Lenovo Flex 5 from Costco, which works flawlessly for audio.

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densmahbb
1 Copper

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

seem like All dell laptop having this issues. Other Brand have find a way to fix it and Dell doesn't care. If you going to use it for Audio or audio matters to you dont buy Dell.

I have same issues with new XPS  (returned) and now precision same issue. if not resolved will go with lenovo

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Sharktopuss
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

Just got a G7 15 7588 a few weeks ago and I've got the same "DPC latency from ACPI.sys" issue. Anyone have a fix or does this thing need to go back to Dell?

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Sharktopuss
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

Sure wish Dell would do something about this. Looks like we're waiting in line for a fix that is YEARS in the making. My 7588 is *almost* a great machine. C'mon Dell! Give us a fix.

Anutka Kzn
1 Nickel

Re: High DPC latency from ACPI.sys on Latitude 7389 causing

Have anyone got any response from DELL so far on the DPC latency? 

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