EFI Timeout variable is ignored (initialized to default on every boot)

EFI Timeout variable is ignored (initialized to default on every boot)

[Andrei Borzenkov]

Using 202005 version I am not able to change "Boot Maintenance Manager"
- "Auto Boot Time-out" or set Timeout variable from within Linux with
efibootmgr - value is overwritten with default (normally 0) on every
boot. The only possibility is to use -boot menu=on QEMU option. Looking
at code, PlatformBootManagerBeforeConsole() unconditionally sets Timeout
to value obtained from GetFrontPageTimeoutFromQemu() which in turn
returns PcdPlatformBootTimeOut (default 0) if nothing was present on
command line (or in general passed via fw_cfg).

I'd expect that default should be current value of Timeout unless
overridden by command line/fw_cfg. It is OK to initialize it for the
first time to PcdPlatformBootTimeOut if Timeout was not defined, but
certainly not every time on every boot.

Re: [edk2-devel] EFI Timeout variable is ignored (initialized to default on every boot)

[Laszlo Ersek]

Hi,

On 07/11/20 15:12, Andrei Borzenkov wrote:
> Using 202005 version I am not able to change "Boot Maintenance Manager"
> - "Auto Boot Time-out" or set Timeout variable from within Linux with
> efibootmgr - value is overwritten with default (normally 0) on every
> boot. The only possibility is to use -boot menu=on QEMU option. Looking
> at code, PlatformBootManagerBeforeConsole() unconditionally sets Timeout
> to value obtained from GetFrontPageTimeoutFromQemu() which in turn
> returns PcdPlatformBootTimeOut (default 0) if nothing was present on
> command line (or in general passed via fw_cfg).
> 
> I'd expect that default should be current value of Timeout unless
> overridden by command line/fw_cfg. It is OK to initialize it for the
> first time to PcdPlatformBootTimeOut if Timeout was not defined, but
> certainly not every time on every boot.

BdsDxe overwrites the Timeout non-volatile variable with
PcdPlatformBootTimeOut, before calling PlatformBootManagerBeforeConsole().

OvmfPkg platform code does not write to the Timeout non-volatile
variable. OvmfPkg platform code only sets PcdPlatformBootTimeOut (from
fw_cfg), but that happens only after BdsDxe has overwritten Timeout with
PcdPlatformBootTimeOut.

https://bugzilla.tianocore.org/show_bug.cgi?id=2488#c1

Laszlo