[U-Boot] [PATCH 14/18] efi: stub: Pass EFI GOP information to U-Boot payload

[Alexander Graf]

On 11.06.18 01:29, Bin Meng wrote:
> On Mon, Jun 11, 2018 at 3:16 AM, Alexander Graf <agraf at suse.de> wrote:
>>
>>
>> On 10.06.18 15:25, Bin Meng wrote:
>>> If UEFI BIOS has the graphics output protocol (GOP), let's pass its
>>> information to U-Boot payload so that U-Boot can utilize it (eg:
>>> an EFI framebuffer driver).
>>>
>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>
>> Why can't the FB drive determine all of this on its own and just fail
>> probe if no GOP protocol can be found?
>>
> 
> It cannot. Once U-Boot payload is running, the boot services are gone.
> There is no way to determine the GOP protocol.

Interesting. Is there a particular reason you're not preserving boot
services?

It might be quite handy to reuse UEFI block interfaces for example. It
might also be useful to preserve (parts of?) the memory map so we don't
overwrite random SMM code for example.

Maybe I misunderstand the purpose of the UEFI U-Boot support though ;).

Alex