What does lspci -vv "DEVSEL=slow" and "DEVSEL=medium" mean?

What does lspci -vv "DEVSEL=slow" and "DEVSEL=medium" mean?

[Roger Heflin]

Hello,

I have 30+ machines, one machine is slower on using an 
infiniband card than the than the others, 
everything we can find is the same except on the "lspci -vv" the
slow machine reports:

"DEVSEL=slow" 

And all of the rest report:

 "DEVSEL=medium"

Both machines have the same bus speed listed, but this is
known to be somewhat shakey on the driver it is using.

What exactly does this mean?

We know the bios version is the same and we believe the 
bios settings are the same, and that the card
is identical, and in the same slot, and that everything else
is the same. 

                       Roger

Re: What does lspci -vv "DEVSEL=slow" and "DEVSEL=medium" mean?

[Daniel J Blueman]

The device select settings tells the PCI bus how many bus clock ticks
are required between certain PCI bus phases and is dictated by the PCI
device on the bus. It sounds like one of the cards you have has an
older revision ASIC/chip.

Roger Heflin wrote:
> Hello,
>
> I have 30+ machines, one machine is slower on using an
> infiniband card than the than the others,
> everything we can find is the same except on the "lspci -vv" the
> slow machine reports:
>
> "DEVSEL=slow"
>
> And all of the rest report:
>
>  "DEVSEL=medium"
>
> Both machines have the same bus speed listed, but this is
> known to be somewhat shakey on the driver it is using.
>
> What exactly does this mean?
>
> We know the bios version is the same and we believe the
> bios settings are the same, and that the card
> is identical, and in the same slot, and that everything else
> is the same.
>
>                        Roger
___
Daniel J Blueman