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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>usb_calc_bus_time</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1" /><link rel="home" href="index.html" title="The Linux-USB Host Side API" /><link rel="up" href="hcd.html" title="Chapter 6. Host Controller APIs" /><link rel="prev" href="hcd.html" title="Chapter 6. Host Controller APIs" /><link rel="next" href="API-usb-hcd-link-urb-to-ep.html" title="usb_hcd_link_urb_to_ep" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>usb_calc_bus_time</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="hcd.html">Prev</a> </td><th width="60%" align="center">Chapter 6. Host Controller APIs</th><td width="20%" align="right"> <a accesskey="n" href="API-usb-hcd-link-urb-to-ep.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="usb_calc_bus_time"><a id="API-usb-calc-bus-time"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_calc_bus_time —
approximate periodic transaction time in nanoseconds
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">long <strong>fsfuncusb_calc_bus_time </strong>(</code></td><td>int <var class="pdparam">speed</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">is_input</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">isoc</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">bytecount</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2996141"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>speed</code></em></span></dt><dd><p>
from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
</p></dd><dt><span class="term"><em class="parameter"><code>is_input</code></em></span></dt><dd><p>
true iff the transaction sends data to the host
</p></dd><dt><span class="term"><em class="parameter"><code>isoc</code></em></span></dt><dd><p>
true for isochronous transactions, false for interrupt ones
</p></dd><dt><span class="term"><em class="parameter"><code>bytecount</code></em></span></dt><dd><p>
how many bytes in the transaction.
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2996222"></a><h2>Description</h2><p>
Returns approximate bus time in nanoseconds for a periodic transaction.
See USB 2.0 spec section 5.11.3; only periodic transfers need to be
scheduled in software, this function is only used for such scheduling.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="hcd.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="hcd.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-usb-hcd-link-urb-to-ep.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 6. Host Controller APIs </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>usb_hcd_link_urb_to_ep</span></td></tr></table></div></body></html>
