[systemd-devel] WebUSB
Lars Knudsen
larsgk at gmail.com
Mon Jan 9 23:11:16 UTC 2017
I finally managed to make a configuration that *seems* to work and I
realize that I may have had something else blocking the WebUSB interface
(2) while modemmanager was communicating with the CDC_ACM interface (1).
I made a clean arbitrary VID/PID and get what seems to be a functioning
WebUSB (now) while modemmanager sends "AT...AT..." to the CDC interface -
so while I thought the modemmanager grabbed my WebUSB interface part, it
must have been because of a faulty combination on my side - my apologies.
WebUSB actually *does* seem to give immediate "bulk" access to a device
otherwise claimed by modemmanager - a very nice option to have and sorry
for the confusion I had that modemmanager grabbed more interfaces than it
should have.
Still, the original request still stands and please tell me if it's a
viable path:
1. If a device has a WebUSB descriptor, it's most probably *not* a modem -
and should in stead be considered a device that in this rare case needs to
be whitelisted (as modem), while defaulting to not being it. This is to
ease the usage from non-browsers to the same hardware, which can then
happen immediately and not be required to fail and wait over the
modemmanager probing period (30 sec?) - related to modemmanager
2. If a device has a WebUSB descriptor, at least the interface linked to
WebUSB should be made accessible in user land by default so no average user
has to figure out how to do udev rules - related to udev/systemd
my headers that seem to work now for the case above:
Bus 002 Device 089: ID 1209:d010 InterBiometrics
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x1209 InterBiometrics
idProduct 0xd010
bcdDevice 0.01
iManufacturer 1 empriKit
iProduct 2 empriKit|MOTION
iSerial 3 00.01
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 90
bNumInterfaces 3
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 1 AT-commands (v.25ter)
iInterface 0
CDC Header:
bcdCDC 1.10
CDC Call Management:
bmCapabilities 0x03
call management
use DataInterface
bDataInterface 1
CDC ACM:
bmCapabilities 0x02
line coding and serial state
CDC Union:
bMasterInterface 0
bSlaveInterface 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0010 1x 16 bytes
bInterval 16
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x05 EP 5 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Binary Object Store Descriptor:
bLength 5
bDescriptorType 15
wTotalLength 29
bNumDeviceCaps 1
** UNRECOGNIZED: 18 10 05 00 38 b6 08 34 a9 09 a0 47 8b fd a0 76 88 15
b6 65 00 01 57 02
Device Status: 0x0001
Self Powered
On Mon, Jan 9, 2017 at 10:32 PM, Reilly Grant <me at reilly.io> wrote:
> On 2017-01-09 9:55 am, Greg KH wrote:
>
>> On Mon, Jan 09, 2017 at 06:13:04PM +0100, Bjørn Mork wrote:
>>
>>> Greg KH <greg at kroah.com> writes:
>>> > On Mon, Jan 09, 2017 at 09:40:59AM +0000, Kenneth Rohde Christiansen
>>> wrote:
>>> >> Web USB can only grab devices which has special Web USB headers. It
>>> can not
>>> >> grab any USB device.
>>> >>
>>> >> https://wicg.github.io/webusb/#webusb-descriptors
>>> >
>>> > Ah, fun :(
>>> >
>>> > So, we can add a quirk into the kernel cdc-acm driver to never bind to
>>> a
>>> > device that has the wusb platform capability descriptor,
>>>
>>> I fail to see why a quirk should be necessary. New device classes are
>>> expected to use new class/subclass codes distintly different from
>>> anything handled by existing class drivers.
>>>
>>
>> One would hope, but it seems like they want to piggy-back on the cdc-acm
>> spec. But I could be totally wrong here, does anyone have the actual
>> descriptor dump of a device anywhere?
>>
>
> We don't want to piggy-back on the CDC-ACM spec. A WebUSB device should
> always have its interfaces marked vendor-specific. Below is an example of a
> device which implements both a CDC-ACM interface and a WebUSB interface. As
> far as I've noticed ModemManager has not interfered with the browser
> accessing this device but Lars has observed this behavior. What I have had
> to do, however, is add a udev rule which sets ownership on the devnode so
> that the browser can access it as an unprivileged user-space application.
> What would be nice to have from systemd-udevd is a way to write a rule that
> will detect the presence of WebUSB descriptors (which is a BOS capability
> descriptor) and set ownership accordingly.
>
> Bus 002 Device 040: ID 2341:8037 Arduino SA
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.10
> bDeviceClass 0 (Defined at Interface level)
> bDeviceSubClass 0
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x2341 Arduino SA
> idProduct 0x8037
> bcdDevice 1.00
> iManufacturer 1 Arduino LLC
> iProduct 2 Arduino Micro
> iSerial 3 WUARTR
> bNumConfigurations 1
> Configuration Descriptor:
> bLength 9
> bDescriptorType 2
> wTotalLength 98
> bNumInterfaces 3
> bConfigurationValue 1
> iConfiguration 0
> bmAttributes 0xa0
> (Bus Powered)
> Remote Wakeup
> MaxPower 500mA
> Interface Association:
> bLength 8
> bDescriptorType 11
> bFirstInterface 0
> bInterfaceCount 2
> bFunctionClass 2 Communications
> bFunctionSubClass 2 Abstract (modem)
> bFunctionProtocol 1 AT-commands (v.25ter)
> iFunction 0
> Interface Descriptor:
> bLength 9
> bDescriptorType 4
> bInterfaceNumber 0
> bAlternateSetting 0
> bNumEndpoints 1
> bInterfaceClass 2 Communications
> bInterfaceSubClass 2 Abstract (modem)
> bInterfaceProtocol 0 None
> iInterface 0
> CDC Header:
> bcdCDC 1.10
> CDC Call Management:
> bmCapabilities 0x01
> call management
> bDataInterface 1
> CDC ACM:
> bmCapabilities 0x06
> sends break
> line coding and serial state
> CDC Union:
> bMasterInterface 0
> bSlaveInterface 1
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x81 EP 1 IN
> bmAttributes 3
> Transfer Type Interrupt
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0010 1x 16 bytes
> bInterval 64
> Interface Descriptor:
> bLength 9
> bDescriptorType 4
> bInterfaceNumber 1
> bAlternateSetting 0
> bNumEndpoints 2
> bInterfaceClass 10 CDC Data
> bInterfaceSubClass 0 Unused
> bInterfaceProtocol 0
> iInterface 0
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x02 EP 2 OUT
> bmAttributes 2
> Transfer Type Bulk
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0040 1x 64 bytes
> bInterval 0
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x83 EP 3 IN
> bmAttributes 2
> Transfer Type Bulk
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0040 1x 64 bytes
> bInterval 0
> Interface Descriptor:
> bLength 9
> bDescriptorType 4
> bInterfaceNumber 2
> bAlternateSetting 0
> bNumEndpoints 2
> bInterfaceClass 255 Vendor Specific Class
> bInterfaceSubClass 0
> bInterfaceProtocol 0
> iInterface 0
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x04 EP 4 OUT
> bmAttributes 2
> Transfer Type Bulk
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0040 1x 64 bytes
> bInterval 0
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x85 EP 5 IN
> bmAttributes 2
> Transfer Type Bulk
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0040 1x 64 bytes
> bInterval 0
> Binary Object Store Descriptor:
> bLength 5
> bDescriptorType 15
> wTotalLength 57
> bNumDeviceCaps 2
> FIXME: alloc bigger buffer for device capability descriptors
> Device Status: 0x0000
> (Bus Powered)
>
>
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