[转]WM/WINCE代码研读系列之Power Management(6)

下面在对UpdateDeviceState(pds)做具体说明
UpdateDeviceState
{
     //获取当前设备的电源级别最大值(ceilingDx)和最小值(floorDx)
     GetNewDeviceStateInfo
     {
          1.对于newCeilingDx
          //首先每个系统电源状态都对应一个默认的所有设备的最大电源级别
          newCeilingDx = psps->defaultCeilingDx;
 
         //在链表gpCeilingDx里查找特定的一类设备的最大电源级别
          devId.pGuid = pds->pListHead->pGuid;
          devId.pszName = NULL;
          if((pdpr = PowerRestrictionFindList(pCeilingDxList,&devId,NULL))!= NULL)
          {
                  newCeilingDx = pdpr->devDx;
          }
 
         //在链表gpCeilingDx里寻找特定的某个设备的最大电源级别
          devId.pszName = pds->pszName;
          if((pdpr = PowerRestrictionFindList(pCeilingDxList,&devId,NULL)) != NULL)
          {
                newCeilingDx = pdpr->devDx;
          }
 
          2.对于newFloorDx
          newFloorDx = D4;//先设置为最小电源级别D4
         //在链表gpFloorDx 里去查找某一类设备的最小电源级别
          devId.pszName = NULL;
          pdpr = pFloorDxList;
          while((pdpr = PowerRestrictionFindList(pdpr,&devId,NULL))!= NULL)