Re: [edk2-devel] EFI_AUDIO_OUTPUT_PROTOCOL: assistance with VirtIO initialization

["Laszlo Ersek" <lersek@redhat.com>]

On 07/01/21 20:10, Ethin Probst wrote:
> The first: I don't know how to retrieve the descriptors on the UEFI
> API. I've looked at the Chaos Key DXE, if memory serves, or the
> display port one -- one of the two. One of them contained a
> ReadDescriptor() function, and so I've borrowed that, but that doesn't
> really help much.

Does the stuff in "MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c" help?

(I don't know how that's exposed, if at all, through UEFI protocols, alas.)

I've added Hao and Ray to the address list (IIUC they maintain the USB
modules in edk2).

Thanks
Laszlo

> 
> On 7/1/21, Michael Brown <mcb30@ipxe.org> wrote:
>> On 01/07/2021 00:01, Ethin Probst wrote:
>>> So Leif and I have been working on USB Audio but we've run into a snag.
>>> We've encountered a problem -- neither of us knows enough about USB to
>>> figure out how to get the class-specific AC interface descriptors, and
>>> those contain vital information that I need to be able to control the
>>> audio device.
>>
>> Do you mean that you can't figure out how to retrieve the descriptors
>> via the UEFI APIs, or that you don't know how to interpret the
>> descriptors after retrieval?
>>
>> Thanks,
>>
>> Michael
>>
> 
>