Hello Andrew,
As per UEFI Spec EFI_ALREADY_STARTED is treated as error code, thus PciIo (The
Interface 3rd parameter ) should remain NULL.
But after OpenProtocol call even though Status = EFI_ALREADY_STARTED PciIo
(The Interface 3rd parameter ) is getting modified and it not NULL anymore.
Is this not a problem ?
Status = gBS->OpenProtocol (
Controller,
&gEfiPciIoProtocolGuid,
(VOID **) &PciIo,
This->DriverBindingHandle,
Controller,
EFI_OPEN_PROTOCOL_BY_DRIVER
);
________________________________
From: [email protected] <[email protected]> on behalf of Andrew Fish
<[email protected]>
Sent: Thursday, June 1, 2017 10:28:16 PM
To: Amit kumar
Cc: [email protected]
Subject: Re: [edk2] Problem in EFI_BOOT_SERVICES.OpenProtocol()
> On Jun 1, 2017, at 9:46 AM, Amit kumar <[email protected]> wrote:
>
> Hi,
> I am trying to open PciIoProtocol and facing some issue.
>
> below is the code
>
> EFI_PCI_IO_PROTOCOL *PciIo=NULL;
> EFI_STATUS Status;
>
> Status = gBS->OpenProtocol (
> Controller,
> &gEfiPciIoProtocolGuid,
> (VOID **) &PciIo,
> This->DriverBindingHandle,
> Controller,
> EFI_OPEN_PROTOCOL_BY_DRIVER
> );
>
> it returns Status = EFI_ALREADY_STARTED, but PciIo is not NULL.
> Is it not supposed to return PciIo as NULL ?
> As per UEFI 2.6 Spec Section 6.3 page 182.
>
Amit,
Look at the Status Codes Returned section at the end of that section.
Attributes is BY_DRIVER and there is an item on the open list with an attribute
of BY_DRIVER whose agent handle is the same as AgentHandle.
Attributes is BY_DRIVER|EXCLUSIVE and there is an item on the open list with an
attribute of BY_DRIVER|EXCLUSIVE whose agent handle is the same as AgentHandle.
Thanks,
Andrew Fish
> There are a number of reasons that this function call can return an error. If
> an error is returned, then
> AgentHandle, ControllerHandle, and Attributes are not added to the list of
> agents
> consuming the protocol interface specified by Handle and Protocol, and
> Interface is
> returned unmodified.
>
> Thanks And Regards
> Amit
> _______________________________________________
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> [email protected]
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