Re: [PATCH] MdeModulePkg/PciBusDxe: make BAR degradation dependent on OPROM presence

[Laszlo Ersek <lersek@redhat.com>]

On 09/12/16 15:16, Ard Biesheuvel wrote:
> On 12 September 2016 at 14:15, Yao, Jiewen <jiewen.yao@intel.com> wrote:
>> HI Ard
>> We should not let MdeModulePkg depend on IntelFrameworkPkg.
>> You patch violates the dependency rule.
>> I suggest we figure out other solution to resolve the problem.
>>
> 
> Yes, please. And please keep us informed about any solutions you come up with.

* One idea is to parse the PCI expansion ROM in order to see what image
types are contained within. If there is no (Code type == 0x00) image in
the oprom, then the oprom is useless for legacy boot anyway, so it
shouldn't trigger degradation.

Unfortunately, this wouldn't help a lot in practice, since it's surely
going to be years before hw vendors migrate to pure UEFI oproms on their
graphics and network cards. :(

* Another idea is to check a dynamic PCD that the platform can set. New
PCDs are frowned upon in MdeModulePkg however, so I don't expect this to
be a popular fix.

Thanks
Laszlo