doc/html/ref/power-attached.html

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  12 >Attached and Detached Controllers</TITLE
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  82 NAME="POWER-ATTACHED">Attached and Detached Controllers</H1
  83 ><DIV
  84 CLASS="REFNAMEDIV"
  85 ><A
  86 NAME="AEN15902"
  87 ></A
  88 ><H2
  89 >Name</H2
  90 >Attached and Detached Controllers&nbsp;--&nbsp;control which power controllers are affected by global changes</DIV
  91 ><DIV
  92 CLASS="REFSYNOPSISDIV"
  93 ><A
  94 NAME="AEN15905"><H2
  95 >Synopsis</H2
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 106 ><TD
 107 ><PRE
 108 CLASS="FUNCSYNOPSISINFO"
 109 >#include &lt;cyg/power/power.h&gt;</PRE
 110 ></TD
 111 ></TR
 112 ></TABLE
 113 ><P
 114 ><CODE
 115 ><CODE
 116 CLASS="FUNCDEF"
 117 >    cyg_bool power_get_controller_attached
 118   </CODE
 119 >(    PowerController* controller
 120   );</CODE
 121 ></P
 122 ><P
 123 ><CODE
 124 ><CODE
 125 CLASS="FUNCDEF"
 126 >    void power_set_controller_attached
 127   </CODE
 128 >(    PowerController* controller
 129   ,     cyg_bool new_state
 130   );</CODE
 131 ></P
 132 ><P
 133 ></P
 134 ></DIV
 135 ></DIV
 136 ><DIV
 137 CLASS="REFSECT1"
 138 ><A
 139 NAME="AEN15920"
 140 ></A
 141 ><H2
 142 >Detaching Power Controllers</H2
 143 ><P
 144 >By default the global operation <TT
 145 CLASS="FUNCTION"
 146 >power_set_mode</TT
 147 >
 148 affects all power controllers. There may be circumstances when this is
 149 not desirable. For example if a particular device is not currently
 150 being used then it can be left switched off: the rest of the system
 151 could be moving between <SPAN
 152 CLASS="TYPE"
 153 >active</SPAN
 154 >, <SPAN
 155 CLASS="TYPE"
 156 >idle</SPAN
 157 > and
 158 <SPAN
 159 CLASS="TYPE"
 160 >sleep</SPAN
 161 > modes, but there is no point in invoking the power
 162 controller for the unused device. To support this the power management
 163 package supports the concept of attached and detached controllers. By
 164 default all controllers are attached, and hence will be affected by
 165 global mode changes. A specific controller can be detached using the
 166 function <TT
 167 CLASS="FUNCTION"
 168 >power_set_controller_attached</TT
 169 >. This
 170 function takes two arguments, one to specify a particular controller
 171 and another to specify the desired new state.
 172 <TT
 173 CLASS="FUNCTION"
 174 >power_get_controller_attached</TT
 175 > can be used to
 176 determine whether or not a specific controller is currently attached.</P
 177 ><P
 178 >The attached or detached state of a controller only affects what
 179 happens during a global mode change, in other words following a call
 180 to <TT
 181 CLASS="FUNCTION"
 182 >power_set_mode</TT
 183 >. It is still possible to
 184 manipulate a detached controller using
 185 <TT
 186 CLASS="FUNCTION"
 187 >power_set_controller_mode</TT
 188 > or
 189 <TT
 190 CLASS="FUNCTION"
 191 >power_set_controller_mode_now</TT
 192 >.</P
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