Laszlo,
The OsIndications will be processed before boot the first boot option, detail
process is in PlatformBdsEnterFrontPage function.
(IntelFrameworkModulePkg/Universal/BdsDxe/FrontPage.c)
BdsEntry() -> PlatformBdsPolicyBehavior() -> PlatformBdsEnterFrontPage().
//
// goto FrontPage directly when EFI_OS_INDICATIONS_BOOT_TO_FW_UI is set
//
OsIndication = 0;
DataSize = sizeof(UINT64);
Status = gRT->GetVariable (
L"OsIndications",
&gEfiGlobalVariableGuid,
NULL,
&DataSize,
&OsIndication
);
//
// goto FrontPage directly when EFI_OS_INDICATIONS_BOOT_TO_FW_UI is set. Skip
HotkeyBoot
//
if (!EFI_ERROR(Status) && ((OsIndication & EFI_OS_INDICATIONS_BOOT_TO_FW_UI)
!= 0)) {
......
Thanks,
Eric
-----Original Message-----
From: Laszlo Ersek [mailto:ler...@redhat.com]
Sent: Tuesday, October 21, 2014 7:14 PM
To: edk2-devel list
Subject: [edk2] BDS: should BootOrder or OsIndications take priority?
Section "7.5.4 Exchanging information between the OS and Firmware" in the UEFI
spec seems to imply that if bit 0 is set in both OsIndicationsSupported and
OsIndications, then at next boot the firmware should stop at the firmware UI.
It appears that this OS-side request is independent of, and prevails over, any
BootOrder and Boot#### settings.
Is the above interpretation correct? And if so, does the Intel BDS driver
diverge from it?
Namely,
BdsEntry()
[IntelFrameworkModulePkg/Universal/BdsDxe/BdsEntry.c]
BdsFormalizeEfiGlobalVariable()
// verifies the size, contents, and
// attributes of "OsIndications",
// but doesn't act upon it
PlatformBdsPolicyBehavior() [...]
// might rework Boot#### and
// BootOrder
BdsBootDeviceSelect()
[IntelFrameworkModulePkg/Universal/BdsDxe/BdsEntry.c]
// invokes the firmware UI only if:
// - no active boot option, or
// - all active boot options
// failed to boot, or
// - an active boot option
// succeded, and returned to the
// firmware.
PlatformBdsEnterFrontPage()
[IntelFrameworkModulePkg/Universal/BdsDxe/FrontPage.c]
// looks at OsIndications
That is, the driver seems to enforce a "formal correctness" of "OsIndications"
early enough, but the code that would *act* upon it is never reached if there
is at least one active and successful boot option that boots an OS.
In other words, the Intel BDS code seems to favor BootOrder and Boot#### above
OsIndications. Is that a divergence from the UEFI spec?
Thanks,
Laszlo
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