NAME

usb_pipe_reset - Abort queued requests from a USB pipe and reset the pipe

SYNOPSIS

#include <sys/usb/usba.h>
void usb_pipe_reset(dev_info_t *dip,


     usb_pipe_handle_t pipe_handle, usb_flags_t usb_flags,


     void (*callback)(usb_pipe_handle_t cb_pipe_handle,


     usb_opaque_t arg, int rval, usb_cb_flags_t flags),


     usb_opaque_t callback_arg);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

dip

Pointer to the device's dev_info structure.

pipe_handle

Handle of the pipe to reset. Cannot be the handle to the default control pipe.

usb_flags

USB_FLAGS_SLEEP is the only flag recognized. Wait for completion.

callback

Function called on completion if the USB_FLAGS_SLEEP flag is not specified. If NULL, no notification of completion is provided.

callback_arg

Second argument to callback function.

DESCRIPTION

Call usb_pipe_reset() to reset a pipe which is in an error state, or to abort a current request and clear the pipe. The usb_pipe_reset() function can be called on any pipe other than the default control pipe.

A pipe can be reset automatically when requests sent to the pipe have the USB_ATTRS_AUTOCLEARING attribute specified. Client drivers see an exception callback with the USB_CB_STALL_CLEARED callback flag set in such cases.

Stalls on pipes executing requests without the USB_ATTRS_AUTOCLEARING attribute set must be cleared by the client driver. The client driver is notified of the stall via an exception callback. The client driver must then call usb_pipe_reset() to clear the stall.

The usb_pipe_reset() function resets a pipe as follows:

1. Any polling activity is stopped if the pipe being reset is an interrupt or isochronous pipe.

2. All pending requests are removed from the pipe. An exception callback, if specified beforehand, is executed for each aborted request.

3. The pipe is reset to the idle state.

Requests to reset the default control pipe are not allowed. No action is taken on a pipe which is closing.

If USB_FLAGS_SLEEP is specified in flags, this function waits for the action to complete before calling the callback handler and returning. If not specified, this function queues the request and returns immediately, and the specified callback is called upon completion.

callback is the callback handler. It takes the following arguments:

usb_pipe_handle_t cb_pipe_handle

Handle of the pipe to reset.

usb_opaque_t callback_arg

Callback_arg specified to usb_pipe_reset().

int rval

Return value of the reset call.

usb_cb_flags_t callback_flags

Status of the queueing operation. Can be:

USB_CB_NO_INFO — Callback was uneventful.

USB_CB_ASYNC_REQ_FAILED — Error starting asynchronous request.

RETURN VALUES

Status is returned to the caller via the callback handler's rval argument. Possible callback handler rval argument values are:

USB_SUCCESS

Pipe successfully reset.

USB_INVALID_PIPE

pipe_handle specifies a pipe which is closed or closing.

USB_INVALID_ARGS

dip or pipe_handle arguments are NULL. USB_FLAGS_SLEEP is clear and callback is NULL.

USB_INVALID_CONTEXT

Called from interrupt context with the USB_FLAGS_SLEEP flag set.

USB_INVALID_PERM

pipe_handle specifies the default control pipe.

USB_FAILURE

Asynchronous resources are unavailable. In this case, USB_CB_ASYNC_REQ_FAILED is passed in as the callback_flags arg to the callback handler.

Exception callback handlers of interrupt-IN and isochronous-IN requests which are terminated by these commands are called with a completion reason of USB_CR_STOPPED_POLLING.

Exception handlers of incomplete bulk requests are called with a completion reason of USB_CR_FLUSHED.

Exception handlers of unstarted requests are called with USB_CR_PIPE_RESET.

Note that messages mirroring the above errors are logged to the console logfile on error. This provides status for calls which could not otherwise provide status.

CONTEXT

May be called from user or kernel context regardless of arguments. May be called from any callback with the USB_FLAGS_SLEEP clear. May not be called from a callback executing in interrupt context if the USB_FLAGS_SLEEP flag is set.

If the USB_CB_ASYNC_REQ_FAILED bit is clear in usb_cb_flags_t, the callback, if supplied, can block because it is executing in kernel context. Otherwise the callback cannot block. Please see usb_callback_flags(9S) for more information on callbacks.

EXAMPLES

void post_reset_handler(


    usb_pipe_handle_t, usb_opaque_t, int, usb_cb_flags_t);
/*


 * Do an asynchronous reset on bulk_pipe.


 * Execute post_reset_handler when done.


 */
usb_pipe_reset(dip, bulk_pipe, 0, post_reset_handler, arg);
/* Do a synchronous reset on bulk_pipe. */
usb_pipe_reset(dip, bulk_pipe, USB_FLAGS_SLEEP, NULL, NULL);

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Architecture	PCI-based systems
Interface stability	Committed