USB_CONTROL_MSG

NAME

SYNOPSIS

int usb_control_msg(struct usb_device * dev, unsigned int pipe, __u8 request, __u8 requesttype, __u16 value, __u16 index, void * data, __u16 size, int timeout);

ARGUMENTS

dev

pointer to the usb device to send the message to

pipe

endpoint lqpiperq to send the message to

request

USB message request value

requesttype

USB message request type value

value

USB message value

index

USB message index value

data

pointer to the data to send

size

length in bytes of the data to send

timeout

time in msecs to wait for the message to complete before timing out (if 0 the wait is forever)

CONTEXT

!in_interrupt ()  

DESCRIPTION

This function sends a simple control message to a specified endpoint and waits for the message to complete, or timeout.

If successful, it returns the number of bytes transferred, otherwise a negative error number.

Don't use this function from within an interrupt context, like a bottom half handler. If you need an asynchronous message, or need to send a message from within interrupt context, use usb_submit_urb. If a thread in your driver uses this call, make sure your disconnect method can wait for it to complete. Since you don't have a handle on the URB used, you can't cancel the request.  

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