Re: Problem in EFI_BOOT_SERVICES.OpenProtocol()

[Andrew Fish <afish@apple.com>]

> On Jun 1, 2017, at 10:40 AM, Amit kumar <akamit91@hotmail.com> wrote:
> 
> Certainly i will do that.
> Meanwhile can i submit the patch too ?

Yes as long as you follow the process. 

Thanks,

Andrew Fish

> Amit
> From: afish@apple.com <mailto:afish@apple.com> <afish@apple.com <mailto:afish@apple.com>> on behalf of Andrew Fish <afish@apple.com <mailto:afish@apple.com>>
> Sent: Thursday, June 1, 2017 11:08:59 PM
> To: Amit kumar
> Cc: edk2-devel@lists.01.org <mailto:edk2-devel@lists.01.org>
> Subject: Re: [edk2] Problem in EFI_BOOT_SERVICES.OpenProtocol()
>  
> 
>> On Jun 1, 2017, at 10:37 AM, Amit kumar <akamit91@hotmail.com <mailto:akamit91@hotmail.com>> wrote:
>> 
>> Hello Andrew,
>> 
>> Thanks for quick reply and acknowledging my query.
>> 
> 
> Please file a bugzilla against the code. 
> 
> Thanks,
> 
> Andrew Fish
> 
>> Amit   
>> From: afish@apple.com <mailto:afish@apple.com> <afish@apple.com <mailto:afish@apple.com>> on behalf of Andrew Fish <afish@apple.com <mailto:afish@apple.com>>
>> Sent: Thursday, June 1, 2017 10:59:03 PM
>> To: Amit kumar
>> Cc: edk2-devel@lists.01.org <mailto:edk2-devel@lists.01.org>
>> Subject: Re: [edk2] Problem in EFI_BOOT_SERVICES.OpenProtocol()
>>  
>> 
>> > On Jun 1, 2017, at 10:13 AM, Amit kumar <akamit91@hotmail.com <mailto:akamit91@hotmail.com>> 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 <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: afish@apple.com <mailto:afish@apple.com> <afish@apple.com <mailto:afish@apple.com>> on behalf of Andrew Fish <afish@apple.com <mailto:afish@apple.com>>
>> > Sent: Thursday, June 1, 2017 10:28:16 PM
>> > To: Amit kumar
>> > Cc: edk2-devel@lists.01.org <mailto:edk2-devel@lists.01.org>
>> > Subject: Re: [edk2] Problem in EFI_BOOT_SERVICES.OpenProtocol()
>> > 
>> > 
>> >> On Jun 1, 2017, at 9:46 AM, Amit kumar <akamit91@hotmail.com <mailto:akamit91@hotmail.com>> 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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>> >> https://lists.01.org/mailman/listinfo/edk2-devel <https://lists.01.org/mailman/listinfo/edk2-devel>
>> > 
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