Eric W. Biederman wrote:
coreboot tracker svn@coreboot.org writes:
#110 Allow for per-device subsystem IDs
What is the proper procedure for saying per-device subsystem IDs is a dumb idea.
The subsystem IDs roughly identify the PCB a component sits on. So unless you have multiple pluggable boards in a system there should only be one subsystem vendor and one subsystem device id.
Is this the official definition? Where does this originate from?
In practice the subsystem vendor IDs are quite arbitrary and definitely not the same for all PCI devices per mainboard on any of the mainboards we have here. In fact, what I have seen quite often is that every PCI device has it's device/vendor ID set as subsystem IDs.
The subsystem information is used by lspci to correctly identify some devices. Plus, more importantly, we use it in flashrom to identify mainboards. Using a unique device ID per board will require us to have two sets of information, one for legacy bios and one for coreboot.
While using per-board subsystem ids sounds the right thing as per your reasoning, I vote to not enforce that behavior, but make it configurable.
Stefan