// this structure describes a set of power manageable devices

typedef struct _DeviceList_tag {

??? LPCGUID???? pGuid;????????????????? // class of device

??? PDEVICE_STATE pList;??????????????? // pointer to devices

??? HANDLE????? hMsgQ;????????????????? // device notification queue

??? HANDLE????? hnClass;??????????????? // handle from RequestDeviceNotifications()

??? PDEVICE_INTERFACE????? pInterface; // interface to the device class power management routines

??? struct _DeviceList_tag *pNext;????? // singly linked list pointer

} DEVICE_LIST, *PDEVICE_LIST;

; Power Manager interfaces.? These list the interface classes that the Power

; Manager will monitor for new devices.

;

[HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/Power/Interfaces]

??? "{A32942B7-920C-486b-B0E6-92A702A99B35}"="Generic power-manageable devices"

??? "{8DD679CE-8AB4-43c8-A14A-EA4963FAA715}"="Power-manageable block devices"

; @CESYSGEN IF CE_MODULES_NDIS

??? "{98C5250D-C29A-4985-AE5F-AFE5367E5006}"="Power-manageable NDIS miniports"

; @CESYSGEN ENDIF CE_MODULES_NDIS

; @CESYSGEN IF CE_MODULES_GWES

??? "{EB91C7C9-8BF6-4a2d-9AB8-69724EED97D1}"="Power-manageable display"

; @CESYSGEN ENDIF CE_MODULES_GWES

// this structure describes a power-manageable device

typedef struct _DeviceState_tag {

??? LPCTSTR???? pszName;??????????????? // device's name

??? CEDEVICE_POWER_STATE??? curDx;????? // current official power state (not necessarily supported by the device)

??? CEDEVICE_POWER_STATE??? floorDx;??? // minimum device power state, or PwrDeviceUnspecified

??? CEDEVICE_POWER_STATE??? ceilingDx;? // maximum device power state, or PwrDeviceUnspecified

??? CEDEVICE_POWER_STATE??? setDx; ?????// power state if explicitly set, or PwrDeviceUnspecified

??? CEDEVICE_POWER_STATE??? lastReqDx;? // last state requested by the device

??? CEDEVICE_POWER_STATE??? actualDx;?? // current actual device power state

??? CEDEVICE_POWER_STATE??? pendingDx;? // Pending DX for updating

??? DWORD?????????????????? dwNumPending; // Number of Pending for updating.

??? struct _DeviceState_tag *pParent;?? // parent device, or NULL

??? POWER_CAPABILITIES????? caps;?????? // as reported by the device

??? DWORD???? ??dwRefCount;???????????? // structure can be deallocated when this is 0

??? HANDLE????? hDevice;??????????????? // handle to the device from OpenDevice(), or NULL

??? PDEVICE_INTERFACE?????? pInterface; // interface to the device class power management routines

??? struct _DeviceList_tag? *pListHead; // pointer to the containing list

??? struct _DeviceState_tag *pNext;???? // linked list pointers

??? struct _DeviceState_tag *pPrev;

} DEVICE_STATE, *PDEVICE_STATE;

// this routine determines to which device list a particular device class

// corresponds

PDEVICE_LIST

GetDeviceListFromClass(LPCGUID guidDevClass)

{

??? PDEVICE_LIST pdl;

??? SETFNAME(_T("GetDeviceListFromClass"));

?

??? PREFAST_DEBUGCHK(guidDevClass != NULL);

?

??? // look for a match

??? __try {

??????? for(pdl = gpDeviceLists; pdl != NULL; pdl = pdl->pNext) {

??????????? if(*pdl->pGuid == *guidDevClass) {

??????????????? break;

???? ???????}

??????? }

??? }

??? __except(EXCEPTION_EXECUTE_HANDLER) {

??????? PMLOGMSG(TRUE, (_T("%s: exception accessing guidDevClass 0x%08x/r/n"),

??????????? pszFname, guidDevClass));

??????? pdl = NULL;

??? }

?

??? return pdl;

}

// This routine looks for a device on a list.? If it finds the device, it

// increments its reference counter and returns a pointer to it.? The caller

// should decrement the reference counter when it is done with the pointer.

// Note that the search is case sensitive.

PDEVICE_STATE

DeviceStateFindList(PDEVICE_LIST pdl, LPCTSTR pszName)

{

??? PDEVICE_STATE pds;

??? SETFNAME(_T("DeviceStateFindList"));

?

??? PMLOCK();

?

??? __try {

??????? // look for a match

??????? for(pds = pdl->pList; pds != NULL; pds = pds->pNext) {

??????????? if(_tcscmp(pds->pszName, pszName) == 0) {

??????????????? // increment the reference count and exit

??????????????? DeviceStateAddRef(pds);

??????????????? break;

??????????? }

??????? }

??? }

??? __except(EXCEPTION_EXECUTE_HANDLER) {

??????? PMLOGMSG(ZONE_WARN, (_T("%s: exception searching list/r/n"), pszFname));

??????? pds = NULL;

??? }

?

??? PMUNLOCK();

?

??? return pds;

}

typedef struct _DeviceInterface_tag {

??? BOOL (WINAPI * pfnInitInterface) (VOID);

??? HANDLE (WINAPI *pfnOpenDevice) (struct _DeviceState_tag *);

??? BOOL (WINAPI * pfnCloseDevice) (HANDLE);

??? BOOL (WINAPI * pfnRequestDevice) (HANDLE, DWORD, LPVOID, DWORD, LPVOID, DWORD, LPDWORD);

} DEVICE_INTERFACE, *PDEVICE_INTERFACE;

// This routine reads the registry to determine what type of device interfaces

// we will be monitoring.? The default PM GUID is ignored if present in the

// registry and is always added last (so it's first in the list).

BOOL

DeviceListsInit(VOID)

{

??? BOOL fOk = TRUE;

??? PDEVICE_LIST pdl;

??? DWORD dwStatus;

??? HKEY hk;

??? TCHAR szBuf[MAX_PATH];

??? SETFNAME(_T("DeviceListsInit"));

?

??? // enumerate all the device classes

???? // 到注冊表[HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/Power/Interfaces]下

???? // 獲取GUID的值，默認情況下，ICLASS共有類別，此處直接通過枚舉的方式查詢到每一個GUID

??? wsprintf(szBuf, _T("%s//Interfaces"), PWRMGR_REG_KEY);

??? dwStatus = RegOpenKeyEx(HKEY_LOCAL_MACHINE, szBuf, 0, 0, &hk);

??? if(dwStatus == ERROR_SUCCESS) {

??????? DWORD dwIndex = 0;

??????? do {

??????????? DWORD cbValueName = dim(szBuf), dwType;

??????????? GUID idInterface;

?

??????????? dwStatus = RegEnumValue(hk, dwIndex, szBuf, &cbValueName, NULL,

??????????????? &dwType, NULL, NULL);

??????????? if(dwStatus == ERROR_SUCCESS) {

??????????????? if(dwType != REG_SZ) {

??????????????????? PMLOGMSG(ZONE_WARN, (_T("%s: invalid type for value '%s'/r/n"),

??????????????????????? pszFname, szBuf));

??????????????? }

?????????????????? // 將GUID進行轉換

?????????????????? else if(!ConvertStringToGuid(szBuf, &idInterface)) {

??????????????????? PMLOGMSG(ZONE_WARN, (_T("%s: can't convert '%s' to GUID/r/n"),

??????????????????????? pszFname, szBuf));

??????????????? }

?????????????????? // 如果是通用設備的GUID，則跳過，留到最后進行初始化其DEVICE_LIST

?????????????????? else if(idInterface == idGenericPMDeviceClass) {

??????????????????? PMLOGMSG(ZONE_INIT, (_T("%s: default GUID found in registry as expected/r/n"),

??????????????????????? pszFname));

??????????????? }

?????????????????? // 為特定GUID類分配并初始化一個DEVICE_LIST結構體變量

?????????????????? else if((pdl = DeviceListCreate(&idInterface)) == NULL) {

??????????????????? PMLOGMSG(ZONE_WARN, (_T("%s: DeviceListCreate() failed/r/n"),

??????????????????????? pszFname));

??????????????? }

?????????????????? // 初始化上面分配的DEVICE_LIST結構體變量的成員pInterface，使其指向有效的函數指針結構體

?????????????????? // 函數PlatformDeviceListInit這里非常重要，它初始化了DEVICE_LIST結構體變量的成員pInterface，而pInterface的具體實現包括gDisplayInterface和gStreamInterface，在pmstream.cpp和pmdisplay.cpp可以找到其具體的實現，代碼寫的蠻經典的

?????????????????? // 這些函數指針結構體通過PM Driver的MDD層獲得

?????????????????? else if(PlatformDeviceListInit(pdl) == FALSE) {

??????????????????? PMLOGMSG(ZONE_WARN, (_T("%s: PlatformDeviceListInit() failed/r/n"),

??????????????????????? pszFname));

??????????????????? DeviceListDestroy(pdl);

??????????????? }

?????????????????? // 將當前GUID的DEVICE_LIST結構體變量添加鏈表gpDeviceLists中

?????????????????? else {

??????????????????? // add the new entry to the list

??????????????????? pdl->pNext = gpDeviceLists;

??????????????????? gpDeviceLists = pdl;

??????????????? }

?

??????????????? // update the index

??????????????? dwIndex++;

??????????? }

?????? ?} while(dwStatus == ERROR_SUCCESS);

?

??????? // check for abnormal termination of the loop

??????? if(dwStatus != ERROR_NO_MORE_ITEMS) {

??????????? fOk = FALSE;

??????? }

?

??????? // close the registry handle

??????? RegCloseKey(hk);

??? }

?

// add the default list last

// 通用設備類留在最后進行初始化，為什么？

// 主要是為了讓通用設備類保持在gpDeviceLists的最前面，利于后面的處理

??? if(fOk) {

??????? fOk = FALSE;

??????? pdl = DeviceListCreate(&idGenericPMDeviceClass);

??????? if(pdl != NULL) {

??????????? if(PlatformDeviceListInit(pdl) == FALSE) {

??????????????? PMLOGMSG(ZONE_INIT || ZONE_WARN,

??????????????????? (_T("%s: PlatformDeviceListInit() failed for default class/r/n"),

??????????????????? pszFname));

??????????????? DeviceListDestroy(pdl);

??????????? } else {

??????????????? pdl->pNext = gpDeviceLists;

??????????????? gpDeviceLists = pdl;

??????????????? fOk = TRUE;

??????????? }

??????? }

??? }

?

??? // clean up if necessary

??? if(!fOk) {

??????? PMLOGMSG(ZONE_WARN, (_T("%s: error during list initialization/r/n"),

??????????? pszFname));

??????? while(gpDeviceLists != NULL) {

??????????? pdl = gpDeviceLists;

??????????? gpDeviceLists = pdl->pNext;

??????????? pdl->pNext = NULL;

??????????? DeviceListDestroy(pdl);

??????? }

??? }

?

??? return fOk;

}

// this thread waits for power manageable devices to be announced.? When

// they arrive they are added to the PM's list of devices and initialized

// appropriately.? If a device goes away, its entry will be removed

// from the list.

DWORD WINAPI

PnpThreadProc(LPVOID lpvParam)

{

??? DWORD dwStatus;

??? HANDLE hnGeneric = NULL;

??? HANDLE hevReady = (HANDLE) lpvParam;

??? HANDLE hEvents[MAXIMUM_WAIT_OBJECTS];

??? DWORD dwNumEvents = 0;

??? BOOL fDone = FALSE;

??? BOOL fOk;

??? INT iPriority;

??? PDEVICE_LIST pdl;

??? SETFNAME(_T("PnpThreadProc"));

?

??? PMLOGMSG(ZONE_INIT, (_T("+%s: thread 0x%08x/r/n"), pszFname, GetCurrentThreadId()));

?

??? // set the thread priority

??? if(!GetPMThreadPriority(_T("PnPPriority256"), &iPriority)) {

??????? iPriority = DEF_PNP_THREAD_PRIORITY;

??? }

??? CeSetThreadPriority(GetCurrentThread(), iPriority);

?

??? // first list entry is the exit event

??? hEvents[dwNumEvents++] = ghevPmShutdown;

?

??? // set up device notifications

??? for(pdl = gpDeviceLists; pdl != NULL && dwNumEvents < dim(hEvents); pdl = pdl->pNext) {

??????? hEvents[dwNumEvents++] = pdl->hMsgQ;

???????? // 有幾個GUID類別，就申請幾個通知

??????? pdl->hnClass = RequestDeviceNotifications(pdl->pGuid, pdl->hMsgQ, TRUE);

??????? if(pdl->hnClass == NULL) {

??????????? PMLOGMSG(ZONE_WARN, (_T("%s: RequestDeviceNotifications() failed %d/r/n"),

??????????????? pszFname, GetLastError()));

??????? }

??? }

??? DEBUGCHK(dwNumEvents > 1);

?

??? // we're up and running

??? SetEvent(hevReady);

?

??? // wait for new devices to arrive

??? while(!fDone) {

??????? dwStatus = WaitForMultipleObjects(dwNumEvents, hEvents, FALSE, INFINITE);

?? ?????if(dwStatus == (WAIT_OBJECT_0 + 0)) {

??????????? PMLOGMSG(ZONE_WARN, (_T("%s: shutdown event set/r/n"), pszFname));

??????????? fDone = TRUE;

??????? } else if(dwStatus > WAIT_OBJECT_0 && dwStatus <= (WAIT_OBJECT_0 + MAXIMUM_WAIT_OBJECTS)) {

?????? ?????dwStatus -= WAIT_OBJECT_0;

????????????? // 收到通知就就對特定GUID設備的電源狀態進行獲取

??????????? fOk = ProcessPnPMsgQueue(hEvents[dwStatus]);

??????????? if(!fOk) {

??????????????? PMLOGMSG(ZONE_WARN, (_T("%s: ProcessPnPMsgQueue(0x%08x) failed/r/n"), pszFname,

???????????????? ???hEvents[dwStatus]));

??????????? }

??????? } else {

??????????? PMLOGMSG(ZONE_WARN, (_T("%s: WaitForMultipleObjects() returned %d, status is %d/r/n"),

??????????????? pszFname, dwStatus, GetLastError()));

??????????? fDone = TRUE;

??????????? break;

? ??????}

??? }

?

??? // release resources

??? for(pdl = gpDeviceLists; pdl != NULL; pdl = pdl->pNext) {

??????? if(pdl->hnClass != NULL) StopDeviceNotifications(pdl->hnClass);

??? }

?

??? // all done

??? PMLOGMSG(ZONE_INIT | ZONE_WARN, (_T("-%s: exiting/r/n"), pszFname));

??? return 0;

}

// This routine adds a device to the list associated with its device class.

// This routine does not return a value; it will either create a new

// device state structure and add it to a list or it will not.? If the new

// device duplicates an existing one this routine won't create a new node.

// This routine executes in the context of the PnP thread, which handles

// device interface additions and removals.

VOID

AddDevice(LPCGUID guidDevClass, LPCTSTR pszName, PDEVICE_STATE pdsParent,

????????? PPOWER_CAPABILITIES pCaps)

{

??? SETFNAME(_T("AddDevice"));

?

??? PMLOGMSG(ZONE_DEVICE,

??????? (_T("%s: adding '%s', pdsParent 0x%08x, pCaps 0x%08x to class %08x-%04x-%04x-%04x-%02x%02x%02x%02x%02x%02x/r/n"),

??????? pszFname, pszName, pdsParent, pCaps,

??????? guidDevClass->Data1, guidDevClass->Data2, guidDevClass->Data3,

??????? (guidDevClass->Data4[0] << 8) + guidDevClass->Data4[1], guidDevClass->Data4[2], guidDevClass->Data4[3],

??????? guidDevClass->Data4[4], guidDevClass->Data4[5], guidDevClass->Data4[6], guidDevClass->Data4[7]));

?

??? // figure out onto which list this device should be added

???? // 到DEVICE_LIST鏈表中查詢當前設備所在的GUID類對應的DEVICE_LIST指針

??? PDEVICE_LIST pdl = GetDeviceListFromClass(guidDevClass);

???

??? // did we find the list?

??? if(pdl != NULL) {

??????? // check for duplicates

???????? // 到當前設備所對應的DEVICE_LIST鏈表中查詢是否在名字為pszName的設備

??????? PDEVICE_STATE pds = DeviceStateFindList(pdl, pszName);

???????

??????? // create the device if it doesn't already exist

???????? // 如果不存在，則創建一個

??????? if(pds == NULL) {

??????????? BOOL fOk = FALSE;

????????????? // 為當前設備創建一個DEVICE_STATE節點

??????????? pds = DeviceStateCreate(pszName);

??????????? if(pds != NULL) {

??????????????? // if we are passed the device's capabilities, just copy them

??????????????? // into the structure

??????????????? if(pCaps != NULL) {

??????????????????? __try {

??????????????????????? pds->caps = *pCaps;

??????????????????? }

??????????????????? __except(EXCEPTION_EXECUTE_HANDLER) {

??????????????????????? PMLOGMSG(ZONE_WARN,

??????????????????????????? (_T("%s: exception during capabilities copy from 0x%08x/r/n"),

??????????????????????????? pszFname, pCaps));

??????????????????????? pCaps = NULL;

??????????????????? }

??????????????? }

???????????????

??????????????? // update the device's parent pointer

??????????????? if(pdsParent != NULL) {

??????????????????? DeviceStateAddRef(pdsParent);

??????????????? }

??????????????? pds->pParent = pdsParent;

???????????????

??????????????? // add the new device to its class list

?????????????????? // 將當前設備的DEVICE_STATE加入到guidDevClass對應的DEVICE_LIST鏈表中

??????????????? if(!DeviceStateAddList(pdl, pds)) {

????????????? ??????// deallocate the node, reference count isn't incremented

??????????????????? DeviceStateDecRef(pds);

??????????????????? pds = NULL;

??????????????? } else {

??????????????????? PREFAST_DEBUGCHK(pds->pInterface != NULL);

??????????????????? PREFAST_DEBUGCHK(pds->pInterface->pfnOpenDevice != NULL);

??????????????????? PREFAST_DEBUGCHK(pds->pInterface->pfnRequestDevice != NULL);

??????????????????? PREFAST_DEBUGCHK(pds->pInterface->pfnCloseDevice != NULL);

?????????????????????? // 獲取設備的操作Handle，這里比較重要，調用的其實是MDD層中首先的函數OpenStreamDevice或者OpenDisplayDevice

??????????????????? pds->hDevice = pds->pInterface->pfnOpenDevice(pds);

??????????????????? if(pds->hDevice == INVALID_HANDLE_VALUE) {

??????????????????????? PMLOGMSG(ZONE_WARN, (_T("%s: couldn't open device '%s'/r/n"),

??????????????????????????? pszFname, pszName != NULL ? _T("<NULL>") : pszName));

??????????????????? } else {

??????????????????????? // do we need to request capabilities?

??????????????????????? fOk = TRUE;???????????? // assume success

??????????????? ????????if(pCaps == NULL) {

??????????????????????????? DWORD dwBytesReturned;

??????????????????????????? POWER_RELATIONSHIP pr;

??????????????????????????? PPOWER_RELATIONSHIP ppr = NULL;

??????????????????????????? memset(&pr, 0, sizeof(pr));

????????? ??????????????????if(pds->pParent != NULL) {

??????????????????????????????? PMLOGMSG(ZONE_DEVICE, (_T("%s: parent of '%s' is '%s'/r/n"),

??????????????????????????????????? pszFname, pds->pszName, pds->pParent->pszName));

??????????????????????????????? pr.hParent = (HANDLE) pds->pParent;

??????????????????????????????? pr.pwsParent = pds->pParent->pszName;

??????????????????????????????? pr.hChild = (HANDLE) pds;

??????????????????????????????? pr.pwsChild = pds->pszName;

??????????????????????????????? ppr = &pr;

??????????????????????????? }???????????????????????

???????????????????????????

??????????????????????????? // get the device's capabilities structure

???????????????????????????????? // 有點意思了，呵呵，調用IOCTL_POWER_CAPABILITIES獲取設備所支持的電源狀態這里比較重要，調用的其實是MDD層中首先的函數RequestStreamDevice或者RequestDisplayDevice，對于這兩類設備來說，分別調用到設備驅動中的DeviceIoControl和ExtEscape

??????????????????????????? fOk = pds->pInterface->pfnRequestDevice(pds->hDevice, IOCTL_POWER_CAPABILITIES,

??????????????????????????????? ppr, ppr == NULL ? 0 : sizeof(*ppr),

??????????????????????????????? &pds->caps, sizeof(pds->caps), &dwBytesReturned);

???????????????????????????

??????????????????????????? // sanity check the size in case a device is just returning

??????????????????????????? // a good status on all ioctls for some reason

??????????????????????????? if(fOk && dwBytesReturned != sizeof(pds->caps)) {

??????????????????????????????? PMLOGMSG(ZONE_WARN,

??????????????????????????????????? (_T("%s: invalid size returned from IOCTL_POWER_CAPABILITIES/r/n"),

? ??????????????????????????????????pszFname));

??????????????????????????????? fOk = FALSE;

??????????????????????????? }

??????????????????????? }

?

??????????????????????? // any problems so far?

??????????????????????? if(fOk) {

????????????????????????? ??// determine whether we should request power relationships from a parent device

???????????????????????????????? // 幫助文檔中提到，這里的意思是：

???????????????????????????????? // Set to POWER_CAP_PARENT bit if the device would like to receive an IOCTL_REGISTER_POWER_RELATIONSHIP call after initialization

???????????????????????????????? // BSP中并沒有使用，應該不用關注

??????????????????????????? if((pds->caps.Flags & POWER_CAP_PARENT) != 0) {

??????????????????????????????? pds->pInterface->pfnRequestDevice(pds->hDevice, IOCTL_REGISTER_POWER_RELATIONSHIP,

??????????????????????????????????? NULL, 0, NULL, 0, NULL);

??????????????????????????? }

??????????????????????? }

??????????????????? }

??????????????? }

???????????????

??????????????? // have we read all the configuration information we need from

??????????????? // the new device

??????????????? if(!fOk) {

??????????????????? // no, delete the device

??????????????????? DeviceStateRemList(pds);

??????????????? } else {

??????????????????? // See if the device supports multiple handles.? Power manageable devices

??????????????????? // should allow multiple open handles, but if they don't we will have to open

??????????????????? // one before each access.

??????????????????? HANDLE hDevice = pds->pInterface->pfnOpenDevice(pds);

??????????????????? if(hDevice == INVALID_HANDLE_VALUE) {

??????????????? ????????PMLOGMSG(ZONE_WARN, (_T("%s: WARNING: '%s' does not support multiple handles/r/n"),

??????????????????????????? pszFname));

??????????????????????? pds->pInterface->pfnCloseDevice(pds->hDevice);

??????????????????????? pds->hDevice = INVALID_HANDLE_VALUE;

??????????????????? } else {

??????????????????????? // close the second handle, since we don't need it

??????????????????????? pds->pInterface->pfnCloseDevice(hDevice);

??????????????????? }

???????????????????

??????????????????? // initialize the new device's power state variables

?????????????????????? // 這里就不用說了，更新電源狀態，呵呵

??????????????????? UpdateDeviceState(pds);

??????????????? }

??????????? }

??????? }

???????

??????? // we are done with the device pointer

??????? if(pds != NULL) {

??????????? DeviceStateDecRef(pds);

??????? }

??? } else {

??????? PMLOGMSG(ZONE_WARN, (_T("%s: class for device '%s' not supported/r/n"),

??????????? pszFname, pszName));

??? }

}

Beginning with Windows CE .NET 4.10, power-manageable devices can belong to varying device classes. These device classes consist both of predefined classes as well as custom device classes. The Power Manager APIs that accept device names can also accept class-qualified device names. For example, each of the following names is a valid device name:

·???????????????? COM1:

·???????????????? {A32942B7-920C-486b-B0E6-92A702A99B35}/COM1:

·???????????????? {98C5250D-C29A-4985-AE5F-AFE5367E5006}/CISCO1

·???????????????? {8DD679CE-8AB4-43c8-A14A-EA4963FAA715}/DSK1:

If a class does not qualify a device name, the device is assumed to belong to the default device class. For example, the names COM1: and {A32942B7-920C-486b-B0E6-92A702A99B35}/COM1: are equivalent.