Re: [edk2-devel] [RFC PATCH 2/2] MdeModulePkg/BdsDxe: allow consoles on drivers loaded via Driver####

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

On Mon, 23 Dec 2019 at 15:09, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
> On Thu, 12 Dec 2019 at 10:05, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> >
> > On Thu, 12 Dec 2019 at 09:59, Ni, Ray <ray.ni@intel.com> wrote:
> > >
> > > Ard,
> > > I still cannot understand it.
> > >
> > > Since Driver#### are processed (process = LoadImage + StartImage) after EndOfDxe, they are not deferred.
> > > It means the Driver#### entrypoints are called directly.
> > > Inside the entrypoints, driverbinding protocols are installed.
> > >
> > > After that, EfiBootManagerConnectAllDefaultConsoles () uses driver model logic to start the proper GOP driver.
> > >
> >
> > It only does that if the GOP console is already in the
> > ConIn/ConOut/ConErr variables, no?
> >
> > Today, we have code in the PlatformBdsLib to traverse the PCI
> > hierarchy to populate those ConXXX variables if we encounter any PCI
> > graphics cards, but this is done in
> > PlatformBootManagerBeforeConsole(), so if the Driver#### is loaded
> > *after* PlatformBootManagerBeforeConsole(), it will not be added to
> > ConXXX. So we need to process Driver#### before calling
> > PlatformBootManagerBeforeConsole(), so that the driver is dispatches
> > right after we call DispatchDeferredImages() but before we do the
> > traversal and populate the COnXXX variables.
> >
> > How else do you propose we could make PCI graphics controllers
> > supported by Driver#### options appear in COnXXX before
> > EfiBootManagerConnectAllDefaultConsoles() is called?
> >
>
> Ping?
>
>

Ping again?

> >
> >
> > >
> > > > -----Original Message-----
> > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard Biesheuvel
> > > > Sent: Wednesday, December 11, 2019 6:40 PM
> > > > To: Ni, Ray <ray.ni@intel.com>
> > > > Cc: Laszlo Ersek <lersek@redhat.com>; edk2-devel-groups-io <devel@edk2.groups.io>; Leif Lindholm
> > > > <leif.lindholm@linaro.org>; Gao, Zhichao <zhichao.gao@intel.com>; Ma, Maurice <maurice.ma@intel.com>; Dong, Guo
> > > > <guo.dong@intel.com>; You, Benjamin <benjamin.you@intel.com>
> > > > Subject: Re: [edk2-devel] [RFC PATCH 2/2] MdeModulePkg/BdsDxe: allow consoles on drivers loaded via Driver####
> > > >
> > > > On Mon, 9 Dec 2019 at 09:42, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > > > >
> > > > > On Mon, 9 Dec 2019 at 03:12, Ni, Ray <ray.ni@intel.com> wrote:
> > > > > >
> > > > > > > Exactly. This flow is identical to how option ROMs are processed if
> > > > > > > they are discovered before EndOfDxe signalling completes (which is why
> > > > > > > the Juno platform was broken without the call to
> > > > > > > EfiBootManagerDispatchDeferredImages() in
> > > > > > > PlatformBootManagerBeforeConsole())
> > > > > > >
> > > > > >
> > > > > > Ard,
> > > > > > I checked ArmPkg's PlatformBootManagerLib and found it doesn't
> > > > > > call *DispatchDeferredImages() after signaling EndOfDxe.
> > > > > >
> > > > >
> > > > > It does. We just added this in 0f9395d7c5cc6ae2beaa2d87008fe158d04a8069
> > > > >
> > > > > > The deferred image dispatch mechanism assumes the platform
> > > > > > needs to call the *DispatchDeferredImages() after signaling EndOfDxe.
> > > > > >
> > > > >
> > > > > Indeed.
> > > > >
> > > > > > I don't understand why the deferred image can be loaded with your patch.
> > > > > > They are still deferred because the loading time is before EndOfDxe.
> > > > > >
> > > > >
> > > > > Yes, but because PlatformBootManagerBeforeConsole () does all of this,
> > > > > the only way to get Driver#### to work for consoles on GOP drivers, we
> > > > > need to move it before that call.
> > > >
> > > > Any further comments on this patch?
> > > >
> > > > 
> > >