Entry tags:

usb, usb hub, usb pd

Гля

        ------------------- USB Hub Descriptor -----------------
bDescriptorLength        : 0x0B (11 bytes)
bDescriptorType          : 0x29 (Hub Descriptor)
bNumberOfPorts           : 0x08 (8 Ports)
wHubCharacteristics      : 0x0000
 Power switching         : Ganged
 Compound device         : No
 Over-current protection : Global
 TT Think Time           : At most 8 FS bit times
 Port Indicators         : Not supported
bPowerOnToPowerGood      : 0x0A (20 ms)
bHubControlCurrent       : 0x00 (0 mA)
DeviceRemovable          : 0x00, 0x00
 Bit 0                   : 0 (reserved, any value)
 Bit 1                   : 0 (Device at Port 1 is removable)
 Bit 2                   : 0 (Device at Port 2 is removable)
 Bit 3                   : 0 (Device at Port 3 is removable)
 Bit 4                   : 0 (Device at Port 4 is removable)
 Bit 5                   : 0 (Device at Port 5 is removable)
 Bit 6                   : 0 (Device at Port 6 is removable)
 Bit 7                   : 0 (Device at Port 7 is removable)
 Bit 8                   : 0 (Device at Port 8 is removable)
 Bit 9                   : 0 (unused, must be 0)
 Bit10                   : 0 (unused, must be 0)
 Bit11                   : 0 (unused, must be 0)
 Bit12                   : 0 (unused, must be 0)
 Bit13                   : 0 (unused, must be 0)
 Bit14                   : 0 (unused, must be 0)
 Bit15                   : 0 (unused, must be 0)
Data (HexDump)           : 0B 29 08 00 00 0A 00 00 00 FF FF                  .).........
HubIsBusPowered          : 0x00 (Self Powered)

        ----------------- USB Hub Capabilities ----------------
HubIs2xCapable           : 0 (Is not 2.x capable)
Data (HexDump)           : 00 00 00 00                                       ....

        --------------- USB Hub Capabilities Ex ---------------
HighSpeedCapable         : 0 (No)
HighSpeed                : 0 (No)
MultiTtCapable           : 0 (No)
HubIsMultiTt             : 0 (No)
ArmedWakeOnConnect       : 0 (No)
IsBusPowered             : 0 (No)
IsRoot                   : 1 (Yes)
Data (HexDump)           : 10 00 00 00                                       ....

Другими словами, когда ты раздрочишь принтерный кабель до короткого замыкания, то вырубится весь корневой концентратор, т.е. весь хост контроллер в который он интегрирован. Несмотря на то, что корневой формально Self Powered, спеку по поводу индивидуальных портов всё равно на хую вертели.