X-Fi USB HD - switching from USB1.1 to USB2?

[Pavel Hofman]

Dne 07. 05. 21 v 10:50 Jaroslav Kysela napsal(a):
> Dne 07. 05. 21 v 10:37 Pavel Hofman napsal(a):
>> Hi,
>>
>> The X-Fi USB HD device (and likely the similar 5.1 model too) can run at
>> USB1.1 (with limited samplerates) and USB2 modes (with full specs). In
>> linux the device stays at USB1.1. If connected to Windows with stock
>> windows USB driver the same happens. However, when the Creative
>> proprietary driver is installed, the device switches to USB2 and
>> supports all features. When rebooting to linux without re-plugging, the
>> USB2 mode stays and the device offers its USB2 configurations to
>> snd-usb-audio.
>>
>> We captured USB packets in linux and Win7 with wireshark - both dumps
>> are included. The windows dump shows that in windows as well as in linux
>> the device starts as device 3.5.0 at USB1.1:
>>
>> DEVICE DESCRIPTOR
>>     bLength: 18
>>     bDescriptorType: 0x01 (DEVICE)
>>     bcdUSB: 0x0110
>>     bDeviceClass: Device (0x00)
>>     bDeviceSubClass: 0
>>     bDeviceProtocol: 0 (Use class code info from Interface Descriptors)
>>     bMaxPacketSize0: 64
>>     idVendor: Creative Technology, Ltd (0x041e)
>>     idProduct: Unknown (0x30d7)
>>     bcdDevice: 0x0100
>>     iManufacturer: 1
>>     iProduct: 2
>>     iSerialNumber: 3
>>     bNumConfigurations: 1
>>
>>
>> After USB1.1 enumeration, the windows host controlled by the vendor
>> driver sends a request USR_FUNCTION_ABORT_PIPE to EP IN 6:
>>
>>
>> The EP IN 6  descriptor (from USB1.1 configuration):
>>
>> ENDPOINT DESCRIPTOR
>>     bLength: 7
>>     bDescriptorType: 0x05 (ENDPOINT)
>>     bEndpointAddress: 0x86  IN  Endpoint:6
>>         1... .... = Direction: IN Endpoint
>>         .... 0110 = Endpoint Number: 0x6
>>     bmAttributes: 0x03
>>         .... ..11 = Transfertype: Interrupt-Transfer (0x3)
>>     wMaxPacketSize: 64
>>         ...0 0... .... .... = Transactions per microframe: 1 (0)
>>         .... ..00 0100 0000 = Maximum Packet Size: 64
>>     bInterval: 1
>>
>> The request sent by the host is:
>> USB URB
>>     [Source: host]
>>     [Destination: 3.5.6]
>>     USBPcap pseudoheader length: 27
>>     IRP ID: 0xfffffa80073ee120
>>     IRP USBD_STATUS: USBD_STATUS_SUCCESS (0x00000000)
>>     URB Function: URB_FUNCTION_ABORT_PIPE (0x0002)
>>     IRP information: 0x00, Direction: FDO -> PDO
>>     URB bus id: 3
>>     Device address: 5
>>     Endpoint: 0x86, Direction: IN
>>     URB transfer type: USB IRP Info (0xfe)
>>     Packet Data Length: 0
>>
>>
>> The device responds with a proprietary response, with a different source
>> 3.5.127:
>> USB URB
>>     [Source: 3.5.127]
>>     [Destination: host]
>>     USBPcap pseudoheader length: 27
>>     IRP ID: 0xfffffa80073ee120
>>     IRP USBD_STATUS: USBD_STATUS_SUCCESS (0x00000000)
>>     URB Function: URB_FUNCTION_ABORT_PIPE (0x0002)
>>     IRP information: 0x01, Direction: PDO -> FDO
>>         0000 000. = Reserved: 0x00
>>         .... ...1 = Direction: PDO -> FDO (0x1)
>>     URB bus id: 3
>>     Device address: 5
>>     Endpoint: 0xff, Direction: IN
>>         1... .... = Direction: IN (1)
>>         .... 1111 = Endpoint number: 15
>>     URB transfer type: Unknown (0xff)
>>         [Expert Info (Error/Malformed): USBPcap did not recognize URB
>> Function code (report to desowin.org/USBPcap)]
>>             [USBPcap did not recognize URB Function code (report to
>> desowin.org/USBPcap)]
>>             [Severity level: Error]
>>             [Group: Malformed]
>>     Packet Data Length: 0
>>
>>
>> Immediately after that the device re-connects as 3.6.0 and reports its
>> USB2.0 description:
>>
>> DEVICE DESCRIPTOR
>>     bLength: 18
>>     bDescriptorType: 0x01 (DEVICE)
>>     bcdUSB: 0x0200
>>     bDeviceClass: Device (0x00)
>>     bDeviceSubClass: 0
>>     bDeviceProtocol: 0 (Use class code info from Interface Descriptors)
>>     bMaxPacketSize0: 64
>>     idVendor: Creative Technology, Ltd (0x041e)
>>     idProduct: Unknown (0x30d7)
>>     bcdDevice: 0x0100
>>     iManufacturer: 1
>>     iProduct: 2
>>     iSerialNumber: 3
>>     bNumConfigurations: 1
>>
>> This is a regular USB-audio device which works OK in snd-usb-audio, as
>> tested after rebooting from windows to linux.
>>
>> Please is there any similar case handled by the existing alsa usb driver
>> which we could try to modify and test? My USB skills are not up to
>> writing the required code myself from scratch, unfortunately.
> 
> The switch can be probably implemented in the user space (libusb + udev
> rules). There is something similar for modems (usb_modeswitch).
> 
> 						Jaroslav

Thank you for your useful suggestion. I am trying to send the command
from userspace with pyusb. I can write/read from the given EP, but
honestly, my knowledge of USB details is very poor. I found a discussion
about MS Windows URB_FUNCTION_ABORT_PIPE which presumably is not
available in linux kernel directly, but as usb_clear_halt()
https://linux-usb-devel.narkive.com/jkl4OpsE/urb-function-abort-pipe .
But here I am in user space.

Please what should be the steps in emulating the above captured USB?
Just some quazi-code would suffice, I will find a way to send it from
userspace.

Thank you very much for any help.

Pavel.