PCI Latency time

NTDEV
1

Hi,

My product has custom PCI card that transfers data in real time to an
external device. This is working fine in 1000+ customer sites.

But I have one particular customer where seemingly at random the operation
does not work because the PC cannot meet the real time data transfer
requirement.

I think I have tracked the problem down to something outside of my card
holding the PCI bus and blocking my card from progressing its DMA. My
theory is that something in the customers PC (probably another card) has
its PCI Latency value set to an unfriendly high value.

What I want to do is find out what the PCI Latency value settings are for
all the devices in the PC.

Can anyone point me at a tool I could run to list the PCI Latency value
settings for all the cards in the PC.

Or better still point me at source code for or documentation on how to
write such a utility.

Thanks in advance for any help.

Rgds

Phil McHugh

2

http://www.lecroy.com/ProtocolAnalyzer/ProtocolOverview.aspx?seriesid=193&capid=103&mid=511
http://www.lecroy.com/Support/SoftwareDownload/documents.aspx?cat=300&capid=106&mid=533&smid=

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02/15/2010 07:36 AM
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Subject
[ntdev] PCI Latency time

Hi,

My product has custom PCI card that transfers data in real time to an
external device. This is working fine in 1000+ customer sites.

But I have one particular customer where seemingly at random the operation
does not work because the PC cannot meet the real time data transfer
requirement.

I think I have tracked the problem down to something outside of my card
holding the PCI bus and blocking my card from progressing its DMA. My
theory is that something in the customers PC (probably another card) has
its PCI Latency value set to an unfriendly high value.

What I want to do is find out what the PCI Latency value settings are for
all the devices in the PC.

Can anyone point me at a tool I could run to list the PCI Latency value
settings for all the cards in the PC.

Or better still point me at source code for or documentation on how to
write such a utility.

Thanks in advance for any help.

Rgds

Phil McHugh
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3

You could use !pci command of WinDbg. This may help you.

Igor Sharovar