Re: UEFI EBS() failures on Lenovo T14s

[Johan Hovold]

On Thu, Nov 28, 2024 at 12:05:09PM +0100, Ard Biesheuvel wrote:

> If you're happy to experiment more, you could try and register a
> notification for EFI_EVENT_GROUP_BEFORE_EXIT_BOOT_SERVICES using
> CreateEventEx(), and see if it gets called when ExitBootServices() is
> called. That would at least help narrow it down.

Thanks for the suggestion.

I see the notify function being called when I signal it as well as on
each ExitBootServices().

With an efi_printk() in the callback ExitBootServices() fails as
expected, but with an empty function the kernel seems to start every
time.

Interestingly, ExitBootServices() now succeeds also if I add back the
CloseEvent() call. In fact, it works also if I never signal the event
(i.e. if I just create and close the event).

The patch below should suffice as a workaround I can carry until the
firmware has been fixed.

Johan