On 06/11/2018 08:01 AM, Bin Meng wrote:
Hi Alex,
On Mon, Jun 11, 2018 at 1:52 PM, Alexander Graf agraf@suse.de wrote:
On 11.06.18 01:29, Bin Meng wrote:
On Mon, Jun 11, 2018 at 3:16 AM, Alexander Graf agraf@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@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?
This is EFI payload support with CONFIG_EFI_STUB. Preserving boot services is EFI application, with CONFIG_EFI_APP. For example, see serial_efi.c which is the serial driver that uses EFI's boot services to output characters on the serial port.
Oh, I see. That makes sense now.
Do people actually need CONFIG_EFI_STUB then?
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 ;).
Looks there is some misunderstanding around the EFI payload support.
Yes, I have to admit that I never really cared enough about it to read its documentation though :).
Alex