HAL_USBPortPower
Hardware Abstraction Layer
HAL entry points from RISC OS
ยป HAL_USBPortPower
HAL_USBPortPower
(HAL entry #109)
void HAL_USBPortPower(int bus, int port, int state)
| Entry | |
|---|---|
| bus | Bus/interface number to query |
| port | Port number to modify |
| state | Power state to set: |
| 0 = Power off | |
| 1 = Power on |
| Exit | |
|---|---|
| - |
Use
This is an internal call for OS use only and should not be used by user software.
Used to control the power state of the indicated port.
The availability of this call is indicated via the flag bits of HAL_USBControllerInfo and requires that the HAL has a fixed mapping between the root hub controller number and the physical connectors on the circuit board, for example where the power is controlled via GPIO lines for those connectors. A root hub controller on a PCI card does not match these criteria as the card could be (re)moved, requiring the HAL to carry detection code that is better placed in the controller driver.
See also
Information source: HWSupport.USB.NetBSD.build.c.ohcimodule in CVS
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