[转]WM/WINCE代码研读系列之Power Management(5)

下面是pNewPowerState->EnterState的具体内容
pNewPowerState->EnterState

{
     PmSetSystemPowerState_I(GetStateString(),0 ,0, TRUE);
     {
          if (((!_tcsicmp(szStateName,_T("suspend"))) || (dwStateHint==POWER_STATE_OFF)) &&(fInternal==TRUE))
          {
                   //将用户关闭系统的消息写入周日志里面
                   PMSQM_Set(PMSQM_DATAID_POWER_USER_SHUTDOWNS,1);
           }
 
           PlatformSetSystemPowerState
           {
                  
                    PmUpdateSystemPowerStatesIfChanged
                    RegReadSystemPowerState
 
                    //将PBT_TRANSITION消息发送给所有注册了相应电源管理通知事件的驱动
                    pbb.Message = PBT_TRANSITION;
                    pbb.Flags = pNewSystemPowerState->dwFlags;
                    pbb.Length = _tcslen(pNewSystemPowerState->pszName) + 1;
                    _tcsncpy(pbb.SystemPowerState,pNewSystemPowerState->pszName, pbb.Length);
                    pbb.Length *= sizeof(pbb.SystemPowerState[0]);
                    GenerateNotifications((PPOWER_BROADCAST) &pbb);
 
                    //更新所有Classes的设备的电源状态
                    UpdateAllDeviceStates();
                    {
                             //从gpDeviceLists中遍历各个Device interface classes
                             for(pdl = gpDeviceLists; pdl != NULL; pdl = pdl->pNext) 
                             {
                                   UpdateClassDeviceStates(pdl);
                                   {   
                                         pds = pdl->pList;    //pdl中再遍历各个Device
                                         while(!fDeviceRemoved && pds != NULL) 
                                         {
                                               UpdateDeviceState(pds)
                                               pdsNext = pds->pNext;
                                          }
                                    }
                             }
                     }
 
                //下面就SUSPEND和Resuming这两种特殊情况分别讨论

---

               //1.Suspended
               if((dwNewStateFlags &(POWER_STATE_SUSPEND|POWER_STATE_OFF|
                             POWER_STATE_CRITICAL|POWER_STATE_RESET)) != 0)
                      fSuspendSystem = TRUE;
               GwesPowerDown() //关掉GWES
 
               //关闭除了idBlockDevices Class的设备以外的所有设备电源状态。因为这个时候还要访问注册表，写文件。所以与此相关的idBlockDevices 的电源状态还应暂时不变.
               for(pdl = gpDeviceLists;pdl != NULL;pdl = pdl->pNext)
               {
                       if(*pdl->pGuid != idBlockDevices)
                       UpdateClassDeviceStates(pdl);
                }
 
               //这里会调用IOCTL_HAL_PRESUSPEND，在进入Suspended之前给OEM一个机会去设置一些东西。微软建议OEM实现IOCTL_HAL_PRESUSPEND时清掉唤醒标示。并且强制来一次线程调度
                KernelIoControl(IOCTL_HAL_PRESUSPEND,NULL,0,NULL,0, NULL); 
                iCurrentPriority = CeGetThreadPriority(GetCurrentThread());
                CeSetThreadPriority(GetCurrentThread(),giPreSuspendPriority);
                Sleep(0);
                CeSetThreadPriority(GetCurrentThread(),iCurrentPriority);
 
                //如果[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power]下有L"PageOutAllModules"则
                if(gfPageOutAllModules)
                          PageOutModule(GetCurrentProcess(),PAGE_OUT_ALL_DEPENDENT_DLL);
               //这个用来找出哪个驱动错误的使用了pageable机制
 
                FileSystemPowerFunction(FSNOTIFY_POWER_OFF);  //关闭文件系统
 
              //关闭block device的电源
               pdl = GetDeviceListFromClass(&idBlockDevices);
               UpdateClassDeviceStates(pdl);
 
              //下面是重启的情况
               if((dwNewStateFlags & POWER_STATE_RESET) != 0)
               {
                       //如果是冷启动则CleanReBoot
                       if(_tcscmp(pszName, _T("coldreboot")) == 0)
                              SetCleanRebootFlag();
 
                      //调用OEM去实现的IOCTL_HAL_REBOOT，这个函数不应该返回。
                       KernelLibIoControl((HANDLE)KMOD_OAL,IOCTL_HAL_REBOOT,NULL,0,NULL,0,NULL);
               }
 
              //设置标志位并调PowerOffSystem，这个函数最终会调到OEMPowerOff()
               gfSystemSuspended = TRUE;
               PowerOffSystem();
 
               Sleep(0); //CPU唤醒后强制来此系统调度
               gfSystemSuspended = FALSE; // clear the suspend flag
               gfPasswordOn = 0;

---

               //2. Resuming
             //打开block device的电源
              pdl = GetDeviceListFromClass(&idBlockDevices);
              UpdateClassDeviceStates(pdl);
 
             //打开文件系统
              FileSystemPowerFunction(FSNOTIFY_POWER_ON);
              //打开除了idBlockDevices Class的设备以外的所有设备电源状态
              for(pdl = gpDeviceLists; pdl != NULL; pdl = pdl->pNext)
              {
                    if(*pdl->pGuid != idBlockDevices)
                           UpdateClassDeviceStates(pdl);
              }

              gpfnGwesPowerUp(fWantStartupScreen); //唤醒GWES
 
             //将PBT_RESUME消息发送给所有注册了相应电源管理通知事件的驱动
              pbb.Message = PBT_RESUME;
              pbb.Flags = 0;
              pbb.Length = 0;
              pbb.SystemPowerState[0] = 0;
              GenerateNotifications((PPOWER_BROADCAST) &pbb);

---

         }
     }
 
     m_LastNewState = GetState();//更新电源状态标志
    //激活UserActivity事件
     m_dwEventArray[PM_USER_ACTIVITY_EVENT] = m_pPwrStateMgr->GetUserActivityTimer()->hevActive;
    //重新校正BacklightTimeout，SuspendTimeout，UserIdleTimeout这三个超时器
     m_pPwrStateMgr->ReAdjustTimeOuts();
}