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Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
To: Andrew Fish <afish@apple.com>, devel@edk2.groups.io
Cc: Jeff Brasen <jbrasen@nvidia.com>
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From: "Laszlo Ersek" <lersek@redhat.com>
Message-ID: <6bc5cce8-7e45-9079-d8d4-9f15bdee9f1d@redhat.com>
Date: Wed, 6 Nov 2019 20:58:02 +0100
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On 11/06/19 17:15, Andrew Fish wrote:
>=20
>=20
>> On Nov 6, 2019, at 3:56 AM, Laszlo Ersek <lersek@redhat.com> wrote:
>>
>> On 11/06/19 00:19, Jeff Brasen wrote:
>>> Wouldn't having a variable that we create and delete on every boot put =
unnecessary stress on the SPI-NOR that the variable store lives on?
>>
>> Yes, it most likely would.
>=20
> Should we write a BZ for the variable stack not to update a  variable if =
the data is not changing?

I'm not certain that, in this case, the write action would re-populate
exactly the same Boot#### variable with exactly the same data. It seems
like in the above, UefiBootManagerLib would create a new variable, and
then the PlatformBootManagerLib instance would make it disappear.

I don't think we should push down the recognition of the above pattern
to the variable driver -- the connection should be made at a higher
logical level. Ultimately, both UefiBootManagerLib and
PlatformBootManagerLib get linked into BdsDxe, so the current limitation
is due to API boundaries that we've created ourselves.

Thanks
Laszlo