cvs commit: src/sys/i386/pci pci_bus.c

Nate Lawson nate at
Wed Oct 6 12:16:35 PDT 2004

John Baldwin wrote:
> On Wednesday 06 October 2004 03:22 am, Warner Losh wrote:
>>imp         2004-10-06 07:22:58 UTC
>>  FreeBSD src repository
>>  Modified files:
>>    sys/i386/pci         pci_bus.c
>>  Log:
>>  For legacy PCI bridges, limit memory allocation to the top 32MB of
>>  RAM.  Many older, legacy bridges only allow allocation from this
>>  range.  This only appies to devices who don't have their memory
>>  assigned by the BIOS (since we allocate the ranges so assigned
>>  exactly), so should have minimal impact.
>>  Hoewver, for CardBus bridges (cbb), they rarely get the resources
>>  allocated by the BIOS, and this patch helps them greatly.  Typically
>>  the 'bad Vcc' messages are caused by this problem.
> We really should be looking at the SMAP to find out what the real limits of 
> PCI space are I think since I think the SMAP includes an entry for PCI memory 
> mapped I/O.

YES!  More integrated SMAP awareness is especially important as more 
complex configs appear with different levels of reservation for upper 
memory besides just "reserved" or "available".


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