Hi Ray,

Rev3 adds the UINT32 field OptimalTransferLengthGranularity field to
EFI_BLOCK_IO_MEDIA. A preexisting binary Block I/O producer that uses
this field will set their revision to the higher value and the only
check I see in edk2 (PartitionDxe) on the revision to access this field
checks for >= EFI_BLOCK_IO_PROTOCOL_REVISION3.

If a binary Block I/O producer is built with the new value that is
consumed by a module built with the older value it might ignore the
OptimalTransferLengthGranularity field. I do not see where this is the
case in edk2 other than PartitionDxe which sets the
OptimalTransferLengthGranularity field to zero for Rev3.

You have contributed to this code in the past so feel free to provide
any further insight if needed.

That said, this change was made to fix a bug in the edk2 implementation
to remove a conflict with the UEFI Spec, the two should be in agreement.

I suggest the change be added to the next stable tag release notes so
authors of such modules are made aware they should release an update
with the new revision value.

Thanks,
Michael

On 9/17/2020 6:25 PM, Ni, Ray wrote:
> Mike,
> Have you evaluated the impact to the already-released module that relies on the macro value?
>
> Basically, you changed to a smaller value that may cause a revision3 check fail:
> a released module expects the revision is bigger than 0x31, but the value is 0x1f.
>
> Thanks,
> Ray
>
>> -----Original Message-----
>> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Michael Kubacki
>> Sent: Tuesday, September 15, 2020 2:11 AM
>> To: devel@edk2.groups.io
>> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>; Liu, Zhiguang
>> <zhiguang.liu@intel.com>
>> Subject: [edk2-devel] [PATCH v1 1/1] MdePkg: Correct EFI_BLOCK_IO_PROTOCOL_REVISION3 value
>>
>> From: Michael Kubacki <michael.kubacki@microsoft.com>
>>
>> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2961
>>
>> The value of EFI_BLOCK_IO_PROTOCOL_REVISION3 is currently
>> 0x00020031. However, the value assigned in the UEFI Specification
>> 2.8B is ((2<<16) | (31)) which is 0x0002001F.
>>
>> Cc: Michael D Kinney <michael.d.kinney@intel.com>
>> Cc: Liming Gao <gaoliming@byosoft.com.cn>
>> Cc: Zhiguang Liu <zhiguang.liu@intel.com>
>> Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
>> ---
>>   MdePkg/Include/Protocol/BlockIo.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/MdePkg/Include/Protocol/BlockIo.h b/MdePkg/Include/Protocol/BlockIo.h
>> index 7b332691ede3..3bd76885e11c 100644
>> --- a/MdePkg/Include/Protocol/BlockIo.h
>> +++ b/MdePkg/Include/Protocol/BlockIo.h
>> @@ -201,7 +201,7 @@ typedef struct {
>>
>>   #define EFI_BLOCK_IO_PROTOCOL_REVISION  0x00010000
>>   #define EFI_BLOCK_IO_PROTOCOL_REVISION2 0x00020001
>> -#define EFI_BLOCK_IO_PROTOCOL_REVISION3 0x00020031
>> +#define EFI_BLOCK_IO_PROTOCOL_REVISION3 0x0002001F
>>
>>   ///
>>   /// Revision defined in EFI1.1.
>> --
>> 2.28.0.windows.1
>>
>>
>>
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