usb_get_max_pkts_per_isoc_request(9f) 맨 페이지 - 윈디하나의 솔라나라

개요

섹션
맨 페이지 이름
검색(S)

usb_get_max_pkts_per_isoc_request(9f)

usb_get_max...isoc_request(9F) Kernel Functions usb_get_max...isoc_request(9F)

NAME
       usb_get_max_pkts_per_isoc_request  -  Get maximum number of packets al‐
       lowed per isochronous request

SYNOPSIS
       #include <sys/usb/usba.h>

       uint_t usb_get_max_pkts_per_isoc_request(dev_info_t *dip);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI)

PARAMETERS
       dip    Pointer to the device's dev_info structure.


DESCRIPTION
       The usb_get_max_pkts_per_isoc_request() function  returns  the  maximum
       number  of isochronous packets per request that the host control driver
       can support. This number can be used to determine the maximum amount of
       data which can be handled by a single isochronous request. That  length
       is found by:



         max = usb_get_max_pkts_per_isoc_request(dip) * endpoint_max_packet_size;



       where  endpoint_max_packet_size  is  the  wMaxPacketSize  field  of the
       isochronous endpoint over which the transfer will take place.

RETURN VALUES
       On success, the  usb_get_current_frame_number()  function  returns  the
       maximum  number  of isochronous pkts per request. On failure it returns
       0. The function fails if dip is NULL.

CONTEXT
       May be called from user, kernel or interrupt context.

EXAMPLES
         /*
          * Set up to receive periodic isochronous data, requesting
          * the maximum amount for each transfer.
          */

         int pkt;
         /* Get max packet size from endpoint descriptor. */
         uint_t ep_max_pkt_size = ep_descr.wMaxPacketSize;
         uint_t isoc_pkts_count = usb_get_max_pkts_per_isoc_request(dip);

         /*
          * Allocate an isoc request, specifying the max number of packets
          * and the greatest size transfer possible.
          */
         usb_isoc_req_t *isoc_req = usb_alloc_isoc_req(dip,
             isoc_pkts_count,
             isoc_pkts_count * ep_max_pkt_size,
             USB_FLAGS_SLEEP);

         /* Init each packet descriptor for maximum size. */
         for (pkt = 0; pkt < isoc_pkts_count; pkt++) {
             isoc_req->isoc_pkt_descr[pkt].isoc_pkt_length = ep_max_pkt_size;

         }


         /* Set the length of a packet in the request too. */
         isoc_req->isoc_pkts_length = ep_max_pkt_size;

         /* Other isoc request initialization. */
         ...
         ...

         if (usb_pipe_isoc_xfer(pipe, isoc_req, USB_FLAGS_NOSLEEP) != USB_SUCCESS) {
             ...
         }


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

       tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE  TYPEAT‐
       TRIBUTE  VALUE  _  ArchitecturePCI-based systems _ Interface Stability‐
       Committed _ Availabilitysystem/io/usb


SEE ALSO
       attributes(7), usb_alloc_request(9F), usb_get_current_frame_number(9F),
       usb_pipe_isoc_xfer(9F). usb_ep_descr(9S), usb_isoc_request(9S)

Oracle Solaris 11.4               5 Jan 2004    usb_get_max...isoc_request(9F)
맨 페이지 내용의 저작권은 맨 페이지 작성자에게 있습니다.
RSS ATOM XHTML 5 CSS3