T420: sound buzzes sometimes when playing videos or music

[PeterTWJ]

Hi all

For my case, I used to have intermittent buzzen spike sound for both W510 and W520. When this issues occur, sometimes SmartAudio GUI may stopped responding. That's another reason I uses Dolby drivers for my current W520, it's more stable and have less problems / conflicts with existing hardware. So far with Dolby, I do not have any buzzes / spike issues.

Cheers 

Peter
(Current: W520 4284-A99) (Refunded: W510 4876-A11)

=============================================
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Dolby Home Theater v4 (ThinkMix V2)!

http://forums.lenovo.com/t5/W-Series-ThinkPad-Lapt​ops/W520-Sound-Enhancement-Thread/m-p/451401#M155... 

[pleon]

Well i use this Dolby and i have buzzing anyway, so Dolby is definitely not a solution.

[niklaas]

Today I also tried reinstalling LAN and WLAN drivers manually (w/o using System Update) for solving this issue but without having any success.

[pleon]

I am not sure, but i think the problem is not in network devices drivers, but in microsoft networking drivers managing TCP/IP communication. So its more OS problem then HW drivers problem.

[niklaas]

Could be -- but still we need to solve that problem somehow. 

I ran LatencyMon another time and got this results:

_________________________________________________________________________________________________________
CONCLUSION
_________________________________________________________________________________________________________
Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines belonging to a driver running in your system appear to be executing for too long. At least one detected problem appears to be network related. You may have to disable wireless adapters to get better results. You might have to disable your battery device to get better results. 
LatencyMon has been analyzing your system for 0:50:34 (h:mm:ss)


_________________________________________________________________________________________________________
System Information
_________________________________________________________________________________________________________
Computer name:                                        LEN-T420
OS version:                                           Windows 7 Service Pack 1, 6.1, build: 7601
CPU:                                                  GenuineIntel        Intel(R) Core(TM) i5-2540M CPU @ 2.60GHz
Logical processors:                                   4
RAM:                                                  8463273984 total
VM:                                                   2147352576, free: 986046464


_________________________________________________________________________________________________________
CPU SPEED
_________________________________________________________________________________________________________
Reported CPU speed:                                   2591 MHz
Measured CPU speed:                                   2030 MHz

Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.


_________________________________________________________________________________________________________
MEASURED KERNEL TIMER LATENCIES
_________________________________________________________________________________________________________
Highest measured kernel timer latency (µs):           9473.4205


_________________________________________________________________________________________________________
MEASURED SMIs AND CPU STALLS
_________________________________________________________________________________________________________
Highest measured SMI routine or CPU stall (µs)        18.5699


_________________________________________________________________________________________________________
REPORTED DPCs
_________________________________________________________________________________________________________
Highest DPC routine execution time (µs):              10081.7838
Driver with highest DPC routine execution time:       ACPI.sys - ACPI-Treiber für NT, Microsoft Corporation

Highest reported total DPC routine time (%):          0.3175
Driver with highest DPC total execution time:         ndis.sys - NDIS 6.20-Treiber, Microsoft Corporation

Total time spent in DPCs (%)                          0.6883

DPC count (execution time <250 µs):                   25458911
DPC count (execution time 250-500 µs):                0
DPC count (execution time 500-999 µs):                1654
DPC count (execution time 1000-1999 µs):              24
DPC count (execution time 2000-3999 µs):              4
DPC count (execution time >=4000 µs):                 0


_________________________________________________________________________________________________________
 REPORTED ISRs
_________________________________________________________________________________________________________
Highest ISR routine execution time (µs):              97.7086
Driver with highest ISR routine execution time:       ACPI.sys - ACPI-Treiber für NT, Microsoft Corporation

Highest reported total ISR routine time (%):          0.4890
Driver with highest ISR total time:                   hal.dll - Hardware Abstraction Layer DLL, Microsoft Corporation

Total time spent in ISRs (%)                          0.6820

ISR count (execution time <250 µs):                   11850330
ISR count (execution time 250-500 µs):                0
ISR count (execution time 500-999 µs):                0
ISR count (execution time 1000-1999 µs):              0
ISR count (execution time 2000-3999 µs):              0
ISR count (execution time >=4000 µs):                 0


_________________________________________________________________________________________________________
 REPORTED HARD PAGEFAULTS
_________________________________________________________________________________________________________
Process with highest pagefault count:                 none

Total number of hard pagefaults                       22189
Hard pagefault count of hardest hit process:          20403
Highest hard pagefault resolution time (µs):          315616.6730
Total time spent in hard pagefaults (%):              0.1417
TODO: Number of processes hit:                        0


_________________________________________________________________________________________________________
 PER CPU DATA
_________________________________________________________________________________________________________
CPU 0 ISR count:                                      11850330
CPU 0 ISR highest execution time:                     97.7086
CPU 0 ISR total execution time:                       27950454.2533
CPU 0 DPC count:                                      24952482
CPU 0 DPC highest execution time:                     10068.9857
CPU 0 DPC total execution time:                       277741081.5333
_________________________________________________________________________________________________________
CPU 1 ISR count:                                      0
CPU 1 ISR highest execution time:                     0.0000
CPU 1 ISR total execution time:                       0.0000
CPU 1 DPC count:                                      73562
CPU 1 DPC highest execution time:                     10081.7838
CPU 1 DPC total execution time:                       1027009.2296
_________________________________________________________________________________________________________
CPU 2 ISR count:                                      0
CPU 2 ISR highest execution time:                     0.0000
CPU 2 ISR total execution time:                       0.0000
CPU 2 DPC count:                                      243587
CPU 2 DPC highest execution time:                     455.8394
CPU 2 DPC total execution time:                       1505713.7502
_________________________________________________________________________________________________________
CPU 3 ISR count:                                      0
CPU 3 ISR highest execution time:                     0.0000
CPU 3 ISR total execution time:                       0.0000
CPU 3 DPC count:                                      190965
CPU 3 DPC highest execution time:                     342.6622
CPU 3 DPC total execution time:                       1530419.3948
_________________________________________________________________________________________________________

 This time it was ACPI.sys that was recognized -- and the first time I ran the test with AC main power plugged in.

[niklaas]

Okay, there's a small update. During the weekend I did some research and also had a look at this article: http://www.scottmetoyer.com/archives/my-solution-for-dell-xps-m1530-dpc-latency . So I did all the stuff that's described in this article and finally (again) found out that it's ndis.sys and acpi.sys.

I also experienced that the latencies  that occure if I ran a virtual machine in VirtualBox aren't as high as when I'm connected to the internet. It seems like they're different from the other ones that sometimes happen because they also do not lead to sound buzzes. -- And the "real" ones only appear if I'm using LAN; so it must be an ethernet problem.

The next thing I did was installing the ethernet drivers from Intel but without solving the problem...

Does anybody have an idea? 

[ColonelONeill]

I think it might just be inherent in Windows.

My DPC latencies go up when there's data transfer over wifi, but not enough to affect audio.

Worse comes to worst... try ASIO4ALL?

[johnbrae]

When Playing music is the ac adaptor plugged in

[PeterTWJ]

Hi all

This is the workaround and it resolves the high dpc latency issues. From what I know, High DPC is caused by IPv4 + IPv6 Offloading, which the Intel NIC card or the driver itself cold not handle. 

http://forums.lenovo.com/t5/W-Series-ThinkPad-Laptops/Workaround-for-high-DPC-issues-for-X-T-and-W-0...

I am not sure whether would there be any other complications from other devices and drivers.

Hope it helps!

Cheers 

Peter
(Current: W520 4284-A99) (Refunded: W510 4876-A11)

=============================================

Does someone’s post help you? Give them kudos as a reward, as they will do better to improve 

Mark it as solved if the solution works for you, so it could be reference for others in the future 

Dolby Home Theater v4 (ThinkMix V2)!

http://forums.lenovo.com/t5/W-Series-ThinkPad-Lapt​ops/W520-Sound-Enhancement-Thread/m-p/451401#M155...  

[mojojoj0 · Accepted solution]

If your machine has the intel gibabit 82579LM or V (wired) ethernet chip (many recent lenovo's do), you may benefit from reading this thread (go to the end of thread for the solution).  

http://forums.lenovo.com/t5/T400-T500-and-newer-T-series/DPC-latency-audio-mouse-skip-and-stutter-on...

I had major headaches with DPC latency causing spikes over 200000 microsecs, which caused stuttering/buzzing audio and jerky mouse movement about every 2 minutes whenever using the network. Lenovo support had no idea what to do. Was ready to turn in my machine for a replacement mobo, it was so annoying.  A guy from Germany tried an older HP/intel driver for that eth chip which fixed his problem and mine too.  See the end of the thread for a link to the old driver.  In my case (and several others with the same chip), the driver published by Lenovo was the problem.  This solution is NOT Lenovo-approved, but you can always reinstall the Lenovo driver after trying it.  The driver is signed by intel, though published on HP's website.

mojojoj0

Austin, TX

t420s (41717FU)