Hello Andrew,
Thanks for quick reply and acknowledging my query. Amit ________________________________ From: [email protected] <[email protected]> on behalf of Andrew Fish <[email protected]> Sent: Thursday, June 1, 2017 10:59:03 PM To: Amit kumar Cc: [email protected] Subject: Re: [edk2] Problem in EFI_BOOT_SERVICES.OpenProtocol() > On Jun 1, 2017, at 10:13 AM, Amit kumar <[email protected]> wrote: > > 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 ? > Amit, I agree it looks like the code will fill in the Interface and return EFI_ALREADY_STARTED. And that does seem to conflict with the section of the spec you quote. Good catch. https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Core/Dxe/Hand/Handle.c#L1097 // // This is the protocol interface entry for this protocol // if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) { *Interface = Prot->Interface; } Status = EFI_SUCCESS; ByDriver = FALSE; Exclusive = FALSE; for ( Link = Prot->OpenList.ForwardLink; Link != &Prot->OpenList; Link = Link->ForwardLink) { OpenData = CR (Link, OPEN_PROTOCOL_DATA, Link, OPEN_PROTOCOL_DATA_SIGNATURE); ExactMatch = (BOOLEAN)((OpenData->AgentHandle == ImageHandle) && (OpenData->Attributes == Attributes) && (OpenData->ControllerHandle == ControllerHandle)); if ((OpenData->Attributes & EFI_OPEN_PROTOCOL_BY_DRIVER) != 0) { ByDriver = TRUE; if (ExactMatch) { Status = EFI_ALREADY_STARTED; goto Done; } } if ((OpenData->Attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE) != 0) { Exclusive = TRUE; } else if (ExactMatch) { OpenData->OpenCount++; Status = EFI_SUCCESS; goto Done; } } Thanks, Andrew Fish > 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 >> _______________________________________________ >> edk2-devel mailing list >> [email protected] >> https://lists.01.org/mailman/listinfo/edk2-devel > > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
