About Option ROM scan process

[liaoo]

Dear all,
I have a question about the process of Option ROM scan and maybe you can help me to clarify it

In chapter 6, Bios Boot Specification v1.01 said

The POST sequence is:
1. Power-on initialization
...
- All option ROM must be mapped into system memory between C0000~EFFFFh
2. PnP Option ROM initialization
...
- Option ROM in PnP card will be called in the order of lowest to highest ...

Thus I guess first BIOS should copy the Option ROM to memory for "all" devices then sequentially call its INIT(lowest memory address called first)... Am I correct ?

And in https://sites.google.com/site/pinczakko/...t_func_ext

For example, a device expansion ROM may require 24 KB for its initialization and runtime code, but only 8 KB for the runtime code. The image in the ROM will show a size of 24 KB, so that the POST code copies the whole thing into RAM. Then when the INIT function is running, it can adjust the size byte down to 8 KB. When the INIT function returns, the POST code sees that the runtime size is 8 KB and can copy the next expansion BIOS to the optimum location.

That means after INIT function completed BIOS could release memory and copy the next option ROM to the optimum location.

My question is: what is the current scheme for Option ROM scan ? (assume 3 option ROM to be processed...)

way 1:
- copy OPROM a to memory
- copy OPROM b to memory
- copy OPROM c to memory
- init OPROM a and downsize
- init OPROM b and downsize
- init OPROM c and downsize

way 2:
- copy OPROM a to memory
- init OPROM a and downsize
- copy OPROM b to memory <- OPROM b will be in optimum location !
- init OPROM b and downsize
- copy OPROM c to memory
- init OPROM c and downsize

Thanks !
liaoo

[Stoneage]

Dear all,
I have a question about the process of Option ROM scan and maybe you can help me to clarify it

In chapter 6, Bios Boot Specification v1.01 said

The POST sequence is:
1. Power-on initialization
...
- All option ROM must be mapped into system memory between C0000~EFFFFh
2. PnP Option ROM initialization
...
- Option ROM in PnP card will be called in the order of lowest to highest ...

Thus I guess first BIOS should copy the Option ROM to memory for "all" devices then sequentially call its INIT(lowest memory address called first)... Am I correct ?

And in https://sites.google.com/site/pinczakko/...t_func_ext

For example, a device expansion ROM may require 24 KB for its initialization and runtime code, but only 8 KB for the runtime code. The image in the ROM will show a size of 24 KB, so that the POST code copies the whole thing into RAM. Then when the INIT function is running, it can adjust the size byte down to 8 KB. When the INIT function returns, the POST code sees that the runtime size is 8 KB and can copy the next expansion BIOS to the optimum location.

That means after INIT function completed BIOS could release memory and copy the next option ROM to the optimum location.

My question is: what is the current scheme for Option ROM scan ? (assume 3 option ROM to be processed...)

way 1:
- copy OPROM a to memory
- copy OPROM b to memory
- copy OPROM c to memory
- init OPROM a and downsize
- init OPROM b and downsize
- init OPROM c and downsize

way 2:
- copy OPROM a to memory
- init OPROM a and downsize
- copy OPROM b to memory <- OPROM b will be in optimum location !
- init OPROM b and downsize
- copy OPROM c to memory
- init OPROM c and downsize

Thanks !
liaoo

I think it's way 2 because it's most logic and also on way 1 where do you copy your data when you need to downsize everything? Read here also: http://www.bios-mods.com/forum/Thread-Op...ice?page=2. In the bottom of the thread the op talks about option rom init and resizing.

[svl7]

It is the second way.
And btw, not all oroms need to be at C0000~EFFFFh, this requirement has been lifted for PCIe 3.0 compliant oroms.