DPC latency + audio/mouse skip and stutter on t420s

[lopiuh · Accepted solution]

checked the settings above (ipv6 disable options) and dpc latency was bad.

Using the old driver version from hp site: very good results. Just to let you know....

It's a shame ...

Greets lopiuh

[mojojoj0]

lopiuh,

Thanks.  I'm testing the old HP driver now, it's been 20 mins of low latency even with as much browsing/refreshing/streaming as I can throw.  Max latency of 640 microsecs, no spikes.  

Who would have thought to use an old driver from another manufacturer?  I have the depot shipping box here and was just about to pack it and send back to lenovo to replace the chipset, but if this solves it, no need for the return.  I'll post my experience after a day of testing.  

mojojoj0

Austin, TX

[mojojoj0]

Lopiuh,

That was great advice.  I have no latency after installing the older driver from HP.  But as soon as I install the Lenovo-provided driver 11.12.38.* or later one from MS, or the Intel generic driver (intel no longer publishes the old driver), I see *immediate* problems with latency, mouse and audio stutter.  But use the driver published by HP (specifically version 11.12.36.0, published 5/4/2011) -- Problem solved!  I tested with streaming and browsing for several hours and no spiking or stutter.

Repost of the english language download from HP: 

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=US&swItem=ob-960...

Lenovo: this is strong evidence of a faulty driver for those of us with a t420s (and probably others out there using the intel chip under x64).  I encourage you to review this solution and engineer an update for the Intel 82579LM gigabit adapter, or at minimum, roll back to the older driver or some Lenovo approved derivative so it doesn't cause all of us notebook users such a major headache.  It's very bizarre that we would need to go to another manufacturer to get a working driver...I was ready to return the machine over this issue. You can see the first post in this thread for more details on my machine.

Aside from that adapter problem, I've been pleased with the t420s performance and features.  Thanks again lopiuh.

Sincerely,

mojojoj0

Austin, TX

[PipoDeClown]

---

mojojoj0 wrote:

Lopiuh,

That was great advice.  I have no latency after installing the older driver from HP.  But as soon as I install the Lenovo-provided driver 11.12.38.* or later one from MS, or the Intel generic driver (intel no longer publishes the old driver), I see *immediate* problems with latency, mouse and audio stutter.  But use the driver published by HP (specifically version 11.12.36.0, published 5/4/2011) -- Problem solved!  I tested with streaming and browsing for several hours and no spiking or stutter.

Repost of the english language download from HP: 

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=US&swItem=ob-960...

Lenovo: this is strong evidence of a faulty driver for those of us with a t420s (and probably others out there using the intel chip under x64).  I encourage you to review this solution and engineer an update for the Intel 82579LM gigabit adapter, or at minimum, roll back to the older driver or some Lenovo approved derivative so it doesn't cause all of us notebook users such a major headache.  It's very bizarre that we would need to go to another manufacturer to get a working driver...I was ready to return the machine over this issue. You can see the first post in this thread for more details on my machine.

Aside from that adapter problem, I've been pleased with the t420s performance and features.  Thanks again lopiuh.

Sincerely,

mojojoj0

Austin, TX

---

This also works for my W520, well still latency but no stuttering ... so far

[ColonelONeill]

Lenovo doesn't write these drivers; they repackage the Intel ones, so it's really Intel's fault at this point.

[mojojoj0]

I disagree. Intel publishes a comprehensive guide for materials, voltage, heat, and all sorts of other clock timings, which must meet certain thresholds to have the NIC work properly.  Clearly, this driver was not tested properly on the t420s before being released by Lenovo, whether they 'repackaged' a generic driver or not.  Where the actual problem exists, either with the driver, or the board, or the voltage, or the timings, cannot be known to me since I'm not a chip engineer.  

However, the fact that it causes problems on a standard Lenovo machine, after a system update by Lenovo software, is the *responsibility* of Lenovo engineering to Lenovo customers.  What I am asking for, and what I think is eminently reasonable, is that the Lenovo engineers fully test the driver, and if it does not function on Lenovo equipment, then roll back to a version that works -or- develop one that does work -or- get with Intel to figure out what the problem is.  

FYI, detailed design requirements for the chip from Intel, and who knows if the t420s meets spec:

http://www.intel.com/content/www/us/en/ethernet-controllers/82579-gbe-controller-checklist-vol-2.htm...

http://www.intel.com/content/www/us/en/ethernet-controllers/ethernet-controllers-common-design-check...

mojojoj0

[lopiuh]

uhh, I am so glad, my advice was helpfull. Good feeling to give something back to the community.

Have a great time

lopiuh

[cmon123]

I just want to confirm that this solution worked for my T520 as well. I created a new thread linking to this solution just in case any T520 owners overloked this one.

Thank You!

[bemymonkey]

So, the issue has been posted on this forum for over two months, and is a very serious one. Where is the updated, fixed driver?

[mojojoj0]

Totally agree. Note that the solution worked for me as I've posted before, but when I updated my bios to the latest just today, now the latency issue is back!  Incredibly frustrating.  But I discovered that the auto-update feature had sneakily installed the later Intel network driver.  So I then just reinstalled the old driver, and again no problems.  I keep a copy of the install file in a special folder so I will always have access to it in case HP removes that link, and suggest others do the same.

I have emailed various folks that I thought were connected to Lenovo, I just emailed MARK_LENOVO, the admin of these forums, I've talked to customer support to roll back or fix the network driver -- nobody seems to care about this issue apparently, or they are completely oblivious to it!  But the old driver does function as a workaround for audio issues (however shameful that an HP driver must be used on Lenovo equipment).  I updated the first post in this thread with a clear link to the solution, for convenience of the other users experiencing the problem.

Mojojojo in Austin TX