On Sun, May 16, 2021 at 12:25:27AM +0100, Leah Rowe via SeaBIOS wrote:
From anecdotal reports, sometimes it is useful; I've heard of instances where certain Nvidia graphics cards can, if using the nouveau driver on a GNU+Linux system, be used without running any option ROM, but where the option ROM has certain data tables in it that the driver can use.
If set to 1, this will disable *all* option ROM loading, even SeaVGABIOS. It also affects CSM. In practise, the only time someone would ever use this is if they were using a graphics card in the above scenario. Such a use-case is incredibly rare.
If set to 0, the normal behaviour can be observed (load, and execute). The run time option etc/pci-optionrom-exec will still be in effect.
Unfortunately it's not valid, in the general case, to deploy an option rom and not run it. The option rom itself can alter its size field and roms are known to do that. Without running the rom, it's often not possible to get its size.
If it's not desirable to actually run the rom, you might want to consider hex editing the particular rom binary so that it's entry point just immediately returns.
-Kevin