Message-ID: <4715F8B0.6080107@free.fr>
Date: Wed, 17 Oct 2007 13:57:36 +0200
From: John Sigler <linux.kernel@free.fr>
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To: Martin Mares <mj@ucw.cz>
CC: linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz
Subject: Re: Understanding lspci output
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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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