Re: [edk2-devel] OpenProtocol() giving me EFI_INVALID_PARAMETER

["Andrew Fish" <afish@apple.com>]

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If I `OvmfPkg/builds.sh qemu -usb -device usb-audio -device qemu-xhci` I see 2 USB handle?

When you open EXCLUSIVE you are kicking other people off the handles. I’m not sure that is a good idea for you to do that to every USB handle in the system. If there was a handle that represented a USB to USB bridge seems like you could kick all the children off….

So when you are probing try using GET_PROTOCOL, and only use EXCLUSIVE after you find the device you want to manage. 

Thanks,

Andrew Fish

> On Jul 17, 2021, at 11:10 AM, Ethin Probst <harlydavidsen@gmail.com> wrote:
> 
> Thanks, Andrew. So it appears as though only a single handle exists
> ("AF: DevicePath(..)/Pci(0x1D,0x0)/USB(0x0,0x0)) USBIO") but my app is
> getting two handles, one of which doesn't actually exist. I still am
> unsure why though. Getting verbose info about handle AF yields an
> interface with class 0x01, subclass 0x01, and protocol 0x04, so this
> appears to match the USB audio control interface. However, no audio
> streaming device is available, as I would expect. Attempting to set
> the interface to `1` also fails on the UAC device (though the USB
> specification does note that this is not necessarily an error and may
> just indicate that that interface setting is not supported so my app
> currently just continues on regardless). I am running with qemu args
> `-usb -device usb-audio,... -audiodev ...`. I've tried with `-device
> qemu-xhci ...` but I get the same result.
> 
> On 7/17/21, Andrew Fish <afish@apple.com <mailto:afish@apple.com>> wrote:
>> 
>> 
>>> On Jul 17, 2021, at 10:06 AM, Ethin Probst <harlydavidsen@gmail.com>
>>> wrote:
>>> 
>>> Okay, so I just tried dh -v 7EDE4C18 (that was the handle that I'm
>>> getting from `HandleBuffer()`) and it says "dh: Handle - '7EDE4C18'
>>> not found". So I'm definitely confused because that's what
>>> `HandleBuffer()` is getting me. Should I pre-allocate the buffer?
>>> 
>> 
>> Ethin,
>> 
>> The UEFI Shell `dh` command  UI uses handle numbers from 0 - N as hex
>> digits. You have use these abstract values with the `dh` command. For
>> example:  use `dh -v A1` to see the actual handle value for A1 (7EBA9598).
>> You can search handles that contain a specific protocol...
>> 
>> Shell> dh -p PciIo
>> Handle dump by protocol 'PCIIO'
>> A1: PCIIO DevicePath(PciRoot(0x0)/Pci(0x0,0x0))
>> A2: PCIIO DevicePath(PciRoot(0x0)/Pci(0x1,0x0))
>> A3: PCIIO DevicePath(PciRoot(0x0)/Pci(0x2,0x0))
>> A4: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x0,0x0))
>> A5: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x1,0x0))
>> A6: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x2,0x0))
>> A7: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x3,0x0))
>> A8: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x4,0x0))
>> A9: PCIIO DevicePath(..0)/Pci(0x2,0x0)/Pci(0x5,0x0))
>> AA: PCIIO DevicePath(PciRoot(0x0)/Pci(0x1E,0x0))
>> AB: DiskIO BlockIO FA920010-6785-4941-B6EC-498C579F160A PCIIO
>> DevicePath(..)/Pci(0x1E,0x0)/Pci(0x0,0x0))
>> AC: ISAACPI PCIIO DevicePath(PciRoot(0x0)/Pci(0x1F,0x0))
>> AD: PCIIO DevicePath(PciRoot(0x0)/Pci(0x1F,0x3))
>> Shell> dh -v A1
>> A1: 7EBA9598
>> PCIIO(7EBA8AA8)
>>  Segment #.....: 00
>>  Bus #.........: 00
>>  Device #......: 00
>>  Function #....: 00
>>  ROM Size......: 0
>>  ROM Location..: 00000000
>>  Vendor ID.....: 8086
>>  Device ID.....: 29C0
>>  Class Code....: 00 00 06
>>  Configuration Header :
>>       8680C029070000000000000600000000
>>       00000000000000000000000000000000
>>       000000000000000000000000F41A0011
>>       000000000000000000000000FF000000
>> DevicePath(7EBA9E18)
>>  PciRoot(0x0)/Pci(0x0,0x0)
>> 
>> Thanks,
>> 
>> Andrew Fish
>> 
>>> On 7/17/21, Ethin Probst <harlydavidsen@gmail.com> wrote:
>>>> I mean, possible... The code I'm using to initialize the handle buffer
>>>> is
>>>> this:
>>>> 
>>>> ```C
>>>> EFI_STATUS EFIAPI UefiMain(IN EFI_HANDLE imageHandle, IN
>>>> EFI_SYSTEM_TABLE*
>>>> st) {
>>>> Print(L"Attempting to find USB IO protocol\n");
>>>> UINTN numHandles = 0;
>>>> UINTN i = 0;
>>>> UINT32 UsbStatus = 0;
>>>> EFI_HANDLE* handles = NULL;
>>>> EFI_USB_IO_PROTOCOL* UsbIo = NULL;
>>>> EFI_STATUS status = st->BootServices->LocateHandleBuffer(ByProtocol,
>>>> &gEfiUsbIoProtocolGuid, NULL, &numHandles, &handles);
>>>> if (EFI_ERROR(status)) {
>>>>   Print(L"Cannot find any handles for USB devices, reason: %r\n",
>>>> status);
>>>>   return EFI_ABORTED;
>>>> }
>>>> Print(L"Found %d USB devices; enumerating\n", numHandles);
>>>> for (; i < numHandles; ++i) {
>>>>   Print(L"Trying to open handle %d (%x)... ", i, handles[i]);
>>>>   status = st->BootServices->OpenProtocol(handles[i],
>>>> &gEfiUsbIoProtocolGuid, (void**)&UsbIo, imageHandle, NULL,
>>>> EFI_OPEN_PROTOCOL_EXCLUSIVE);
>>>>   if (EFI_ERROR(status)) {
>>>>     Print(L"%r, skipping\n", status);
>>>>     continue;
>>>>   }
>>>>   // ...
>>>> ```
>>>> I've done my best to follow SEI secure C coding standards, like
>>>> initializing all variables, regardless of type -- e.g. initializing
>>>> pointers to 0/NULL. But I will definitely try that idea.
>>>> 
>>>> On 7/17/21, Andrew Fish <afish@apple.com> wrote:
>>>>> 
>>>>> 
>>>>>> On Jul 17, 2021, at 9:41 AM, Ethin Probst <harlydavidsen@gmail.com>
>>>>>> wrote:
>>>>>> 
>>>>>> Hey all,
>>>>>> 
>>>>>> So my UsbAudio.efi app has hit a bit of a roadblock. This code:
>>>>>> 
>>>>>> ```C
>>>>>>  status = st->BootServices->OpenProtocol(handles[i],
>>>>>> &gEfiUsbIoProtocolGuid, (void**)&UsbIo, imageHandle, NULL,
>>>>>> EFI_OPEN_PROTOCOL_EXCLUSIVE);
>>>>>>  if (EFI_ERROR(status)) {
>>>>>>    Print(L"%r, skipping\n", status);
>>>>>>    continue;
>>>>>>  }
>>>>>> ```
>>>>> 
>>>>> How are you constructing handle[]? Could it have gotten stale? You
>>>>> could
>>>>> print out the value of handle[I] on the failure.
>>>>> 
>>>>> The contents of a handle are not defined, but the current
>>>>> implementation
>>>>> is
>>>>> a pointer to an IHANDLE internal data structure in the DXE Core. If you
>>>>> are
>>>>> at the UEFI Shell and you `dh -v <handleNum> it will show the
>>>>> <handleNum>
>>>>> and the value.
>>>>> 
>>>>> Shell> dh -v 98
>>>>> 98: 6d5CF18
>>>>> ….
>>>>> 
>>>>> I think you can `dh -p UsbIo’ to get the list of the UsbIo handles.
>>>>> 
>>>>> So you can poke around and see what is happening on that handle.
>>>>> 
>>>>> I guess the handle[] array could be getting corrupted? So you could
>>>>> check
>>>>> for that?
>>>>> 
>>>>> Thanks,
>>>>> 
>>>>> Andrew Fish
>>>>> 
>>>>>> Is giving me EFI_INVALID_PARAMETER and I don’t know why. I don't think
>>>>>> I'm violating any of its constraints, according to the specification,
>>>>>> and I haven't touched this code since it was written. It also happens
>>>>>> irregularly: sometimes it happens on the USB audio streaming device,
>>>>>> or if I have a device plugged in it might happen on that device, you
>>>>>> get the idea. But it doesn't consistently fail. Does anybody have any
>>>>>> idea what's going on?
>>>>>> 
>>>>>> --
>>>>>> Signed,
>>>>>> Ethin D. Probst
>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> --
>>>> Signed,
>>>> Ethin D. Probst
>>>> 
>>> 
>>> 
>>> --
>>> Signed,
>>> Ethin D. Probst
>>> 
>>> 
>>> 
>>> 
>>> 
>> 
>> 
> 
> 
> -- 
> Signed,
> Ethin D. Probst
> 
> 
> 


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