Re: Understanding lspci output

[John Sigler <linux.kernel@free.fr>]

Hello Martin,

Martin Mares wrote:

> > I ran lspci -vvv on a system:
> > http://linux.kernel.free.fr/halt/lspci.txt
> >
> > (I used lspci version 2.2.5 in case it matters.)
> >
> > But I'm having a hard time making sense of the output.
> >
> > 1. How many PCI buses are there in the system?
>
> Two, just see the bus numbers of the devices. (However, there might be
> additional buses with no devices present and in case these are connected
> to a separate host bridge, they need not be visible.)
>
> > 4. Does the system have a PCI-X bus?
>
> Yes, the devices on bus 01 are PCI-X devices, so there is a PCI-X bus.

I thought PCI-X devices could operate on a PCI bus? If that is true, 
then the presence of a PCI-X device would not necessarily imply the 
presence of a PCI-X bus, right?

There are no external PCI-X slots in the system, only 2 PCI slots.
The 4 NICs are integrated to the motherboard.
http://advantech.com/products/1U-Rackmount-Intel-Pentium-4Processor-based-Platform-with-4PCI-LAN-Ports-2-PCI-Expansion-Slots/mod_1-23A2W4.aspx

> > 2. Do any of the PCI buses support 66 MHz operation?
>
> Yes, PCI-X does.

So the 01:0f.0 device (Multimedia video controller) is on the same bus 
as the 4 PCI-X devices and will have to share the bus bandwidth?

Does 66MHz+ in the Status line means this device is running at 66 MHz?

> > 3. Do any of the PCI slots support 64-bit data path?
>
> This cannot be inferred from the lspci output -- there is no way how to
> tell if a bus has physical slots or it exists only internally.

Can I use lspci to see whether a specific PCI device is using a 64-bit 
data path? (e.g. the 01:0f.0 device)

Regards.
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