Date: Sun, 15 Aug 2004 01:10:12 -0700 From: Eric Hodel <drbrain@segment7.net> To: current@freebsd.org Subject: ADA-305 - USB Audiocontrol device or proprietary poser? Message-ID: <20040815081012.GZ89329@segment7.net>
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In light of the recent USB threads, I decided now would be a good time
to bring up my USB-controlled speakers.
I have ADA-305 speakers by Altec Lansing. Allegedly they support the
USB audiocontrol interface, and FreeBSD's uaudio driver attempts to
recognize them, but ultimately fails. (In windows there is a nifty
little utility that lets me adjust the volume of each speaker.)
They don't send any audio over USB, they only do volume control.
Here's what uaudio says about the speakers when I plug them in:
uaudio0: audio descriptors make no sense, error=3D4
device_attach: uaudio0 attach returned 6
Here's what udesc_dump says about the speakers:
Standard Device Descriptor:
bLength 18
bDescriptorType 01
bcdUSB 0100
bDeviceClass ff
bDeviceSubClass 00
bDeviceProtocol 00
bMaxPacketSize 8
idVendor 04d2
idProduct 0305
bcdDevice 0000
iManufacturer 1
iProduct 2
iSerialNumber 0
bNumConfigurations 1
Configuration 0:
Standard Configuration Descriptor:
bLength 9
bDescriptorType 02
wTotalLength 25
bNumInterface 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 40 (self-powered)
bMaxPower 0 (0 mA)
Standard Interface Descriptor:
bLength 9
bDescriptorType 04
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 01
bInterfaceSubClass 01
bInterfaceProtocol 00
iInterface 0
Standard Endpoint Descriptor:
bLength 7
bDescriptorType 05
bEndpointAddress 81 (in)
bmAttributes 03 (Interrupt)
wMaxPacketSize 2
bInterval 32
bRefresh 208
bSynchAddress d0
Codes Representing Languages by the Device:
bLength 4
bDescriptorType 03
wLANGID[0] 0409
String (index 1): ALTEC LANSING Multimedia
String (index 2): ADA305 Speakers
I added some debugging, and the attach fails in uaudio_identify_ac on
the following:
id =3D uaudio_find_iface(buf, size, &offs, UISUBCLASS_AUDIOCONTROL);
if (id =3D=3D NULL)
return (USBD_INVAL);
if (offs + sizeof *acdp > size)
return (USBD_INVAL); /* BOOM! */
Here are the values it failed on:
uaudio_identify_ac: offs + sizeof *acdp > size
uaudio_identify_ac: offs =3D 18
uaudio_identify_ac: sizeof *acdp =3D 9
uaudio_identify_ac: size =3D 25
It looks like uaudio_find_iface is incrementing offs even if it found
the correct interface descriptor, so I moved the *offsp +=3D d->bLength;
after the return. (See the lengths from udesc_dump above, is this
a correct fix?.)
I now die just below that here:
ibuf =3D buf + offs;
acdp =3D (struct usb_audio_control_descriptor *)ibuf;
if (acdp->bDescriptorType !=3D UDESC_CS_INTERFACE ||
acdp->bDescriptorSubtype !=3D UDESCSUB_AC_HEADER)
return (USBD_INVAL); /* BOOM! */
Looking at the endpoint descriptor above, the DescriptorType is a
UDESC_ENDPOINT, not a UDESC_CS_INTERFACE. It also has no
DescriptorSubtype.
Are these speakers just pretending to be USB audiocontrol devices and
have some proprietary implementation underneath, or could there be
something mis-detected somewhere else?
--=20
Eric Hodel - drbrain@segment7.net - http://segment7.net
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