From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mx.groups.io with SMTP id smtpd.web10.6954.1625216357499760905 for ; Fri, 02 Jul 2021 01:59:17 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Nbd3hoCe; spf=pass (domain: redhat.com, ip: 216.205.24.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625216356; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oBUZQb7N6ZOPLH/dZ6B2fB8Wmo0r/GH8Dsny165xOXY=; b=Nbd3hoCeOTRZ7SeHKTedNK0YBDoJvCLkIfFCInnq9z1uVF711g2DI9w3v1PJ/DJlhOipm/ Q3oqfYEcX3hsWJfZWgkHdlP7rlGCpGP7tPX+ODD4FnV/ZeUOU/6iGINQzYpPaayjRi1wtw oZrh5SXRtvc8pP+WbFM5FNxJ2aJJN2o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-205-9fkRyBCOPtGO624uKvx8xA-1; Fri, 02 Jul 2021 04:59:15 -0400 X-MC-Unique: 9fkRyBCOPtGO624uKvx8xA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8DECC804140; Fri, 2 Jul 2021 08:59:13 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-114-129.ams2.redhat.com [10.36.114.129]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5DA2F19D7C; Fri, 2 Jul 2021 08:59:12 +0000 (UTC) Subject: Re: [edk2-devel] EFI_AUDIO_OUTPUT_PROTOCOL: assistance with VirtIO initialization To: devel@edk2.groups.io, harlydavidsen@gmail.com, Michael Brown , Ray Ni , Hao A Wu References: From: "Laszlo Ersek" Message-ID: Date: Fri, 2 Jul 2021 10:59:10 +0200 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 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 >> > >