[LinuxBIOS] lpci_set_subsystem question

Segher Boessenkool segher at kernel.crashing.org
Wed Aug 15 23:23:11 CEST 2007

>> Shouldn't the PCI config register always be 0x2c (subsystem ID 
>> register)
>> like in the last example (bcm5780_sb_pci_main.c)? Should these 
>> functions
>> even be there since there is a stock pci_dev_set_subsystem() that 
>> seems
>> to be correct?
> IIRC it should be, but is not always. A lot of chips don't quite
> follow the spec, and this weird out-of-band setting of registers crops
> up. That's my take on it anyway.

The PCI spec only defines the "read" behaviour of the subsystem
config registers as far as I know.  Anything writing those regs
is just as non-standard (or moreso!) as something using special
regs is.


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