[edk2-devel] Bitfield var stores and compatibility

[edk2-devel] Bitfield var stores and compatibility

[Tim Lewis via groups.io]

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Can we discuss the EDK2 extension to allow bitfield varstores that is not a compatible changes and, in fact, inhibits the UEFI spec from going in certain directions.

Back in  2017, the EDK2 version of the browser added the EDKII_IFR_BIT_VARSTORE_GUID, which, if present, tells the EDK2 form browser to change the meaning of almost all fields related to storage, including VarOffset, size and uses the bottom 6 bits of the Flags field in the question header.

However, these changes are not found in the UEFI specifications. As a result, any "compliant" browser cannot correctly deal with questions that require these extensions. It is not problem if the form is built at the same time as the rest of the firmware, but 3rd party  drivers, UEFI applications and option ROMs cannot assume that this support is present.

We have run into this when thinking about creating a proposal for the UEFI specification and found that adding bits in the Flags field doesn't work for checkbox, one-of and numeric questions because those bits are already co-opted by this EDK2 extension and this EDK2 extension is being used by some 3rd party drivers.

How did this ever get approved by the maintainers?


Thanks,

Tim

[cid:image002.png@01DBBDA9.1F3EE5A0]
Tim Lewis
CTO
Insyde Software
Phone: +1-916-813-6838




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