Re: [PATCH] ArmVirtPkg: undo bogus component name and driver diagnostics disablement

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

On 15 October 2016 at 17:56, Laszlo Ersek <lersek@redhat.com> wrote:
> The entry point function of any UEFI_DRIVER that conforms to the UEFI
> driver model must install an instance of the EFI_DRIVER_BINDING_PROTOCOL
> on the image handle. Beyond that, the following protocols are optional:
>
> - EFI_COMPONENT_NAME_PROTOCOL
> - EFI_COMPONENT_NAME2_PROTOCOL
> - EFI_DRIVER_CONFIGURATION_PROTOCOL
> - EFI_DRIVER_CONFIGURATION2_PROTOCOL
> - EFI_DRIVER_DIAGNOSTICS_PROTOCOL
> - EFI_DRIVER_DIAGNOSTICS2_PROTOCOL
>
> The UefiLib functions
>
> - EfiLibInstallAllDriverProtocols()
> - EfiLibInstallAllDriverProtocols2()
> - EfiLibInstallDriverBindingComponentName2()
>
> are convenience helpers for such UEFI_DRIVERs. They simplify the
> installation of the above protocols.
>
> The UefiLib instance in "MdePkg/Library/UefiLib/UefiDriverModel.c" allows
> platforms to control these functions through the MdePkg feature PCDs
>
> - PcdComponentNameDisable
> - PcdComponentName2Disable
> - PcdDriverDiagnosticsDisable
> - PcdDriverDiagnostics2Disable
>
> If any of these PCDs are set to TRUE, then the helper functions will not
> install the corresponding protocol interfaces on the image handle, even if
> the driver passes in non-NULL protocol interfaces.
>
> In other words, at build time, a platform can forcibly prevent all drivers
> that employ UefiLib from producing these protocols.
>
> In ArmVirtPkg, that's what we've been doing forever, for no reason at all.
> This is why we haven't been seeing component and driver names from the DH,
> DEVICES, DRIVERS and DEVTREE shell commands, unlike in OvmfPkg.
>
> The default value for all these PCDs is FALSE, in "MdePkg/MdePkg.dec".
> Revert ArmVirtPkg to the sane defaults.
>
> This bug dates back to the inception of ArmVirtPkg (called
> ArmPlatformPkg/ArmVirtualizationPkg at the time).
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Fixes: 6f5872b1f4013f58c6d2f446d885edd6c8ea6d21
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

I always had a suspicion we were missing something here, but I never
got around to tracking it down. Thanks for doing that.

> ---
>  ArmVirtPkg/ArmVirt.dsc.inc | 4 ----
>  1 file changed, 4 deletions(-)
>
> diff --git a/ArmVirtPkg/ArmVirt.dsc.inc b/ArmVirtPkg/ArmVirt.dsc.inc
> index c624b3cdbecd..c071988ad8f5 100644
> --- a/ArmVirtPkg/ArmVirt.dsc.inc
> +++ b/ArmVirtPkg/ArmVirt.dsc.inc
> @@ -254,10 +254,6 @@ [BuildOptions]
>
>  [PcdsFeatureFlag.common]
>    gEfiMdeModulePkgTokenSpaceGuid.PcdHiiOsRuntimeSupport|FALSE
> -  gEfiMdePkgTokenSpaceGuid.PcdComponentNameDisable|TRUE
> -  gEfiMdePkgTokenSpaceGuid.PcdDriverDiagnosticsDisable|TRUE
> -  gEfiMdePkgTokenSpaceGuid.PcdComponentName2Disable|TRUE
> -  gEfiMdePkgTokenSpaceGuid.PcdDriverDiagnostics2Disable|TRUE
>
>    #
>    # Control what commands are supported from the UI
> --
> 2.9.2
>