Re: [edk2-devel] [PATCH 0/5] ArmPkg/PlatformBootManagerLib: play nice without ConnectAll()

["Leif Lindholm" <leif@nuviainc.com>]

On Wed, May 27, 2020 at 07:35:18 +0200, Ard Biesheuvel wrote:
> On 5/27/20 12:01 AM, Leif Lindholm via groups.io wrote:
> > On Tue, May 26, 2020 at 18:13:54 +0200, Ard Biesheuvel wrote:
> > > Currently, Armpkg's PlatformBootManagerLib connects all controller to
> > > their drivers recursively, even if the active boot option does not
> > > require it. There are some historical reasons for this, some of which are
> > > being addressed in separate patches.
> > > 
> > > This series addresses the way ArmPkg's PlatformBootManagerLib implementation
> > > deals with the UEFI Shell and the UiApp: currently, the shell is always
> > > added as an ordinary boot option, which will be started if no other boot
> > > options can be started, or if it is the first one in the boot order.
> > > 
> > > Once we remove the ConnectAll() call from PlatformBootManagerLib, those shells
> > > will be launched without any block or other devices connected, which may
> > > confuse novice users. So before doing so, let's make the handling a bit more
> > > sane:
> > > - add a 's' hotkey that enters the UEFI shell regardless of its priority
> > >    in the BootOrder - this shell will be entered with no devices connected
> > >    after patch #4
> > > - enter the UiApp as a last resort if no boot options can be started
> > > - make the UEFI Shell boot option hidden, so it is not started by default
> > >    (only by hotkey or BootNext)
> > > - remove the ConnectAll() call from PlatformBootManagerLib
> > > - finally, add a plugin library for UiApp to expose the UEFI Shell via an
> > >    ordinary main menu option (this works around the fact that patch #3 will
> > >    result in the UEFI Shell disappearing from the Boot Manager list).
> > >    Entering the shell this way will resemble the old situation, given that
> > >    UiApp connects all devices and refreshes all boot options etc at launch.
> > 
> > I get why this set was sent in isolation, but could we also discuss
> > somewhat what we would plan to do with the edk2-platforms that make
> > use of the ArmPkg PlatformBootManagerLib?
> > 
> > Not attempting a fallback boot onto network is probably an acceptable
> > change to pick up, but having an undocumented hotkey as the only way
> > into a shell that now doesn't map devices could be a bit aggravating.
> > 
> 
> It is not the only way, and it is not even the preferred way. Patch 5/5 adds
> an option to the UiApp root menu to enter the UEFI Shell, in a way that is
> independent from boot option handling. Since you enter UiApp first, all
> handles will be connected and boot options refreshed as usual.
> 
> In cases where you want to avoid this from happening, you can use the 's'
> key to drop into a shell directly.

Yes, that's exactly what I am referring to. But in order for the new
(and I agree improved) functionality to be available, the new Shell
library needs to be explicitly added to .dsc for the platforms affected.

I want an active decision to be made about how that is going to
happen, if it is going to happen, as part of the conversation about
*this* set. Merging this and *then* looking into it makes for too
harsh a break in behaviour.

/
    Leif