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HOWTO: Low DPC latencies (<100 us) on bootcamped Macbooks (Pro)

Hey Timur,
I have this audio problem where it sounds like it's skipping like a CD player when it's bumping heavily. Like the music will play fine then after 30 sec or so, it'll like do this whole delay skipping effected and go back to normal again then repeat.
I tried to use your command stuff and also tried to update the Broadcom drivers but it said I already have the lastest drivers.
I turned off all the bluetooth and ethernet except the wireless because I need the wifi.

It restarted it, and it's doing it still. Any solutions?
 
What do you mean by "your command stuff"? Did you kill KBDMGR.EXE (most important) and try the Rivatuner patch on the graphic-card?
 
Hey timur, do you know if bootcamp 3.0 corrects this issue? also do you know if it has gpu switching??
 
No idea about Bootcamp 3, but the NVidia/graphic-card related problems have little to do with Bootcamp anyway (other than that the Bootcamp package comes with a version of Nvidia drivers). Would be nice if Apple could get Nvidia to fix those issues in a new driver build though. Didn't check lately...
 
Timur said:
No idea about Bootcamp 3, but the NVidia/graphic-card related problems have little to do with Bootcamp anyway (other than that the Bootcamp package comes with a version of Nvidia drivers). Would be nice if Apple could get Nvidia to fix those issues in a new driver build though. Didn't check lately...
Click to expand...

For whatever it matters, I sent driver bug feedback to Nvidia, and some feedback to Apple on this particular issue.

Nothing in particular causes this issue. The power management on MacBook Pro's with the 9600M GT using Nvidia's Graphic Driver causes the computer to often lock up when switching performance mode to or from the Low Performance 2D setting. This has been confirmed with numerous machines and Apple is aware of the issue, but has not issued a fix.

A simple search on google.com will show you the widespread problem: http://www.google.com/search?hl=en&...rformance+2d+freeze&btnG=Search&aq=f&oq=&aqi=

People with Vista and Windows 7 (32 & 64bit) are affected. Windows XP users are not affected because of another bug in the driver that causes the computer to never leave the High Performance 3D setting.

I'm not sure if this has ever been reported, but it is ridiculous that nothing has been fixed in over 6 months of this being a known issue. Probably not Nvidia's problem, and probably something to do with the way the computer manages power consumption, but in any case, it's a problem that shouldn't exist.

By using Rivatuner, we have been able to force a constant performance mode and keeping the computer freeze free, but the average PC user would not know how to go this route, and it is also keeping us from using the newest drivers.

The included driver from Apple also has this issue.

--------------------------------Rest was in addition sent to Apple---------------------------------

This is unacceptable to be a student/professional machine to have a known problem with locking up, especially advertising the computer to run Windows, when in reality, it cannot. False advertisement!

I have called many times about this issue, and Apple tells us to call Microsoft, which is not the answer. It's something up with the Nvidia driver, or the way Apple has configured the 9600M GT to work (unreliable voltage source maybe). In any case, there are tons of the 9600M GT's being used in other brands of computers without this issue. It is just the MacBook Pro's with the issue. It's been almost a year now, and people still cannot run Windows Vista or 7 reliably on a MacBook Pro. I cannot switch operating systems because my university requires Vista 32.

Get this right or I want something other than this "Professional" machine. Spent way too much on this for it to freeze up.
Click to expand...
 
hey timur,
thank you very much, you saved me from having a lot of hassle with "saturn" here in germany, i was about to return my macbook but then i saw your posts :).
i still have one question, did you find another solution/utility for turning off intel's speedstep on bootcamp?

thank you!
 
another big thank you, this problem has been plaguing me for months. i finally decided to do something about it and was trying for hours updating audio drivers and tweaking settings.

it wasn't until i used dpc latency check that i noticed that my audio problems were due to dpc spikes every 1 minute. and it wasn't until i read your post that i was able to pinpoint the problem to the broadcom driver

you did an awesome job documenting this issue!
 
Two download suggestions:

1) For Fireface/Firewire users Microsoft released two hotfixes for the *non*-legacy Firewire port driver. The latest one says:

Transferred data is corrupted or the data transfer stops between an IEEE 1394 device and a computer that is running Windows 7 or Windows Server 2008 R2"
Click to expand...

Transferred data is corrupted or the data transfer stops between an IEEE 1394 device and a computer that is running Windows 7 or Windows Server 2008 R2

2) The following tool is a good substitude for Rivatuner. It allows to switch NVidia Performance Modes without doing a reboot (including to turn on/off adaptive clock-rates to save power when you are not working on audio).

You need to run it "as Administrator" in order for it to detect and change the necessary registry keys. And you might need to have it "Create PowerMizer Settings" to first create those keys because on some setups they are not created by the NVidia driver setup.

PowerMizer Manager | Some More Bytes

PS: While the latest NVidia drivers mostly (but not necessarily completely) fix the huge DPC spikes that happen whenever clock-rates are switched they do not fix the 2D DPC issues on all hardware. My 9600M GT (bootcamped Macbook Pro) isn't fixed for example.
 
Experience with 9600M GT on (bootcamped) Macbook Pro 17" running Windows 7 64-bit (same as 32-bit, same as Vista):

1) Even the latest 257 Beta driver still does not solve the problem of high DPC latencies in 2D (low power) mode. DPC spikes reach well over 1500 us, which in turn can lead to audio-dropout (especially for professional audio users). Neither Performance nor Low-Power 3D modes show these problems.

The same was happening on Vista (while on XP it always ran in "Performance 3D" mode which isn't that much better a solution). I reported this via NVidia temporary "Feedback" form more than a year ago. The only "workaround" for professional audio users is to permanently force the NVidia driver to one of the 3D modes via PowerMizer Manager (recommended!) or Rivatuner.

Here is a trace of 2D mode while running Ableton Live (audio is *disabled*):

xtrace2dtrackpad.png


In one trace run I had exorbitantly high DPC readings via DPC Latency Checker. Interestingly these turned out to be a combination of the Nvidia driver and usbport.sys while using Live's GUI (which is somewhat questionably programmed though and causing its own load of problems).

2) DPC spikes are still happening when performance modes are switched (clock-rates changed), but less than in the past.

2ddpcs.png


3) Like the current WHQL driver with the 257 Beta the GPU is *always* running in Performance 3D mode (maximum clock-rates, heat and power-consumption) when an external display is attached. This did not happen with older version drivers.
 
Current workaround for 330M users:


1) Again use PowerMizer Manager to use a fixed performance level, it should not matter which one so you can also use the power saving 2D mode (may be different on your setup though).

2) Open the NVidia Control Panel and go to "Adjust image settings with preview" (you will see a spining NVidia logo). Put the animation on Pause and minimize the NVidia Control Panel.

3) You may or may not have to do this: Either switch off Aero, or better change the "Compatibility" settings of your DAW application to tell Windows only to turn off Aero (Desktop Composition) for this application.

Also watch out when setting display brightness or speaker volume via key (especially when an overlay is displayed), it may cause dropouts. You can change those by mouse via the respective settings without issues though.
 
AttilaAfra on NVidia forum said:
I still have DPC spikes (about 17000 µs) with the 266.58 driver on my HP EliteBook 8540p with NVS 5100M, Windows 7 64-bit. I've verified this with DPC Latency Checker, LatencyMon, and xperf. I have spikes also with the 266.35, 260.99, and 260.89 drivers. However, there are absolutely no DPC issues with 261.28, which was released only on Windows Update in December, only for Quadros in HP notebooks.
Click to expand...
The NVS 5100 and FX 880 are based on the 330M GT chip. I modified the INF of the Microsoft build to install the FX 880 files for my 330M GT and lo and behold: No more DPC issues, neither in any mode (2D/3D) nor when switching modes.

I will have to do some test to see how professional audio applications are affected, but at the moment it seems that the maximum DPCs caused by the NVidia driver are down to what my rather clumsy workaround achieves.

You can find the modified INF attached to this post: http://forums.nvidia.com/index.php?showtopic=157614&view=findpost&p=1182843
 
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