Re: One problem in reassign pci bus number?
From: Wei Yang
Date: Tue Apr 24 2012 - 10:56:17 EST
2012/4/24 Yinghai Lu <yinghai@xxxxxxxxxx>:
> On Sun, Apr 22, 2012 at 8:52 AM, Richard Yang
> <weiyang@xxxxxxxxxxxxxxxxxx> wrote:
>> All,
>>
>> I am reading the pci_scan_bridge() and not sure what will happen in
>> following situation.
>>
>> Suppose the kernel is not passed the pci=assign-busses.
>>
>> Below is a picture about the pci system.
>>
>> +-------+
>> | | root bridge(0,255)
>> +---+---+
>> | Bus 0
>> -----+-----------+------------------------------+--
>> | |
>> | |
>> | |
>> +----+----+ +-----+-----+
>> | | B1(1,15) | |B2(16,28)
>> +----+----+ +-----+-----+
>> | Bus 1 | Bus 16
>> -----+----------------------- ----------+----------------
>> |
>> +----+----+
>> | | B3
>> +---------+
>>
>> Suppose B1 and B2 works fine with the BIOS, which get the right bus
>> number and range.
>>
>> B3 does not works fine with the BIOS, which doesn't get the bus number.
>>
>> So in pci_scan_bridge(), B3 will be met in the second pass and get bus
>> number 16?
>> Would this be a conflict?
>
> busn_alloc patchset should address your concern.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git
> for-pci-busn-alloc
>
hmm... the code changes too much...
I need more time to understanding it.
while the case i found is different from that reported by Don.
> Yinghai
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--
Richard Yang
Help You, Help Me
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