[systemd-devel] WebUSB
Lars Knudsen
larsgk at gmail.com
Mon Jan 9 23:47:51 UTC 2017
A small update: When the modemmanager finishes probing (~16 secs after
connection) data seems to stop flowing in from the WebUSB bulk endpoint
also. It is, however, possible to reconnect and get data again - so I need
to see if there should be anything in the mbed firmware causing that
behavior or there is some sort of silent reset of interfaces/endpoints
happening on the linux side when probing is done.
On Tue, Jan 10, 2017 at 12:11 AM, Lars Knudsen <larsgk at gmail.com> wrote:
> 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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