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Re: PCI-enum and SouthBridge behaviour...

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On 25/07/2016 10:04, wolfgang kern wrote:
> James Harris wrote:

>>>> Walking the PCI bus (and other busses connected thereto) should
>>>> enumerate everything, shouldn't it, on any PC made in the last 20
>>>> years or so? Before that there was PnP which would also allow
>>>> enumeration.
>
>>> Yes, but its hard to enumerate a device that dont show up.
>>> perhaps thats why windoze need a lot of 'drivers' from mainboard vendor
>>> and several reboot cycles to make all these unseen work.
>
>> Microsoft has always had the big advantage that hardware manufacturers
>> will privately tell MS about their devices.
>
>> That said, Linux has to cope with the same problems. Maybe you could
>> look at the Linux source?
>
> C-source ?  it wont show me much I'm afraid :(

Ah, I forgot who I was writing to...!

Maybe you can convert it to a hex dump. ;-)

...

>>> Meanwhile I have to run my whole PCI-scan one more time after chip-type
>>> recognition and device enabling.
>
>> That may be the only option. I guess that detecting chipset types is
>> not easy to do reliably.
>
> Type detection isn't too hard, just read vendor- and device-ID.

For the chipset? Where from? Something in the PCI scan?

Early machines had motherboard or machine identification in the top 
bytes of the ROM.

...

>> Your PCI scan won't take long, will it?
>
> No, only a few mS if I just scan until all desired are found, but a full
> scan over all possible 256 busses would take seconds.

Wouldn't you only attempt to scan a non-root PCI bus if you discover a 
bridge to it? IIRC PCI configs for bridges give the downstream bus 
number. So you wouldn't need to scan 256 busses unless you had a veeery 
big machine. ;-)

-- 
James Harris

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Thread

PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-22 21:53 +0200
  Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-24 16:52 +0100
    Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-24 19:54 +0200
      Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-25 07:07 +0100
        Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-25 11:04 +0200
          Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-25 10:30 +0100
            Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-25 14:06 +0200
              Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-25 13:16 +0100
                Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-26 13:09 +0200
                Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-26 15:14 +0100
          Re: PCI-enum and SouthBridge behaviour... Rod Pemberton <NoHaveNotOne@bcczxcfrze.cam> - 2016-07-25 21:55 -0400
            Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-26 12:48 +0200
  Re: PCI-enum and SouthBridge behaviour... Rod Pemberton <NoHaveNotOne@bcczxcfrze.cam> - 2016-07-26 08:18 -0400
    Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-26 20:11 +0200
  Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-28 18:53 +0200
    Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-29 19:47 +0200
      Re: PCI-enum and SouthBridge behaviour... Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-07-29 17:44 -0400
        Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-30 09:44 +0200
    Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-30 12:55 +0100
      Re: PCI-enum and SouthBridge behaviour... "wolfgang kern" <nowhere@never.at> - 2016-07-30 19:40 +0200
        Re: PCI-enum and SouthBridge behaviour... James Harris <james.harris.1@gmail.com> - 2016-07-30 19:08 +0100

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