Question

使用NVAPI时遇到NvAPI_DISP_GetDisplayConfig问题。我在第二次调用NvAPI_DISP_GetDisplayConfig时得到一个AppCrash。似乎无法弄清楚原因。

NvU32 count = 0;
status = NvAPI_DISP_GetDisplayConfig(&count, NULL);
if (status != NVAPI_OK) 
    PrintError(status);
printf("Configs: %i\n", count);
NV_DISPLAYCONFIG_PATH_INFO *configinfos = new NV_DISPLAYCONFIG_PATH_INFO[count];
configinfos[0].version = NV_DISPLAYCONFIG_PATH_INFO_VER;
status = NvAPI_DISP_GetDisplayConfig(&count, configinfos);
if (status != NVAPI_OK) 
    PrintError(status);

在我的系统上，第一次通话后count = 2。关于NvAPI_DISP_GetDisplayConfig的说明说：

NVAPI_INTERFACE     NvAPI_DISP_GetDisplayConfig（
    __inout NvU32 * pathInfoCount，
    __out_ecount_full_opt * pathInfoCount NV_DISPLAYCONFIG_PATH_INFO * pathInfo
    ）

描述：此API允许调用者检索当前的全局显示
  配置。
  使用：来电者可能需要拨打三次才能获取所有必需的内容   配置细节如下：
  首次通过：来电者应使用pathInfo设置来调用NvAPI_DISP_GetDisplayConfig（）   为NULL以获取pathInfoCount   第二遍：根据
的数量为pathInfo分配内存   pathInfoCount（从First Pass）到fetch //！ //！ targetInfoCount。如果
  sourceModeInfo需要分配内存，或者可以初始化为NULL   第三次通过（可选，仅在需要目标信息时才需要）：分配
  targetInfo的内存相对于
的数量   targetInfoCount（来自Second Pass）。支持的操作系统：Windows Vista及更高版本

感谢。

编辑：我也试过设置configinfos [0] .sourceModeInfo = NULL无济于事。我也尝试迭代数组以设置所有.version和.sourceModeInfo无效（我在文档中看到的一个例子只在数组中的第一个项目上设置了版本）

Answer 1

这应该适合你：

NvAPI_Status status = NVAPI_OK;
NvU32 deviceCount = 0;
NV_DISPLAYCONFIG_PATH_INFO_V2 *  pathInfo = NULL;

status = NvAPI_Initialize();
if (status == NVAPI_OK) {
    status = NvAPI_DISP_GetDisplayConfig(&deviceCount, pathInfo);
    if ((status == NVAPI_OK) && (deviceCount > 0)) {
        pathInfo = new NV_DISPLAYCONFIG_PATH_INFO_V2[deviceCount];
        for (int i = 0; i < deviceCount; i++)
        {
            pathInfo[i].targetInfo = 0;
            pathInfo[i].targetInfoCount = 0;
            pathInfo[i].version = NV_DISPLAYCONFIG_PATH_INFO_VER2;
            pathInfo[i].sourceModeInfo = 0;
            pathInfo[i].reserved = 0;
        }

        status = NvAPI_DISP_GetDisplayConfig(&deviceCount, pathInfo);

        if (status == NVAPI_OK) {
            for (int i = 0; i < deviceCount; i++)
            {
                pathInfo[i].sourceModeInfo = new NV_DISPLAYCONFIG_SOURCE_MODE_INFO_V1;
                pathInfo[i].sourceModeInfo->reserved = 0;
                pathInfo[i].targetInfo = new NV_DISPLAYCONFIG_PATH_TARGET_INFO_V2[pathInfo[i].targetInfoCount];
                for (int j = 0; j < pathInfo[i].targetInfoCount; j++) {
                    pathInfo[i].targetInfo[j].details = 0;
                }
            }
        }

        status = NvAPI_DISP_GetDisplayConfig(&deviceCount, pathInfo);

        for (int i = 0; i < deviceCount; i++)
        {
            if (pathInfo[i].sourceModeInfo) delete pathInfo[i].sourceModeInfo;
            if (pathInfo[i].targetInfo) delete [] pathInfo[i].targetInfo;
        }
        delete[] pathInfo;
    }
}

Answer 2

马科斯的回答是更彻底的。我相信你的代码中的具体问题是你没有初始化第二个pathInfo。所以你需要添加：

configinfos[1].version = NV_DISPLAYCONFIG_PATH_INFO_VER;

始终保持记忆力也是一种很好的形式。所以在分配后你应该立即：

memset(configinfos, 0, sizeof(NV_DISPLAYCONFIG_PATH_INFO) * count);

或者您可以单独设置值。

Answer 3

NvAPI附带的示例代码中有一个名为DisplayConfiguration的示例，它完全利用了GetDisplayConfig。从DisplayConfiguration.cpp复制粘贴函数：

NvAPI_Status AllocateAndGetDisplayConfig(NvU32* pathInfoCount, NV_DISPLAYCONFIG_PATH_INFO** pPathInfo)
{
    NvAPI_Status ret;

    // Retrieve the display path information
    NvU32 pathCount                         = 0;
    NV_DISPLAYCONFIG_PATH_INFO *pathInfo    = NULL;

    ret = NvAPI_DISP_GetDisplayConfig(&pathCount, NULL);
    if (ret != NVAPI_OK)    return ret;

    pathInfo = (NV_DISPLAYCONFIG_PATH_INFO*) malloc(pathCount * sizeof(NV_DISPLAYCONFIG_PATH_INFO));
    if (!pathInfo)
    {
        return NVAPI_OUT_OF_MEMORY;
    }

    memset(pathInfo, 0, pathCount * sizeof(NV_DISPLAYCONFIG_PATH_INFO));
    for (NvU32 i = 0; i < pathCount; i++)
    {
        pathInfo[i].version = NV_DISPLAYCONFIG_PATH_INFO_VER;
    }

    // Retrieve the targetInfo counts
    ret = NvAPI_DISP_GetDisplayConfig(&pathCount, pathInfo);
    if (ret != NVAPI_OK)
    {
        return ret;
    }

    for (NvU32 i = 0; i < pathCount; i++)
    {
        // Allocate the source mode info
        pathInfo[i].sourceModeInfo = (NV_DISPLAYCONFIG_SOURCE_MODE_INFO*) malloc(sizeof(NV_DISPLAYCONFIG_SOURCE_MODE_INFO));
        if (pathInfo[i].sourceModeInfo == NULL)
        {
            return NVAPI_OUT_OF_MEMORY;
        }
        memset(pathInfo[i].sourceModeInfo, 0, sizeof(NV_DISPLAYCONFIG_SOURCE_MODE_INFO));

        // Allocate the target array
        pathInfo[i].targetInfo = (NV_DISPLAYCONFIG_PATH_TARGET_INFO*) malloc(pathInfo[i].targetInfoCount * sizeof(NV_DISPLAYCONFIG_PATH_TARGET_INFO));
        if (pathInfo[i].targetInfo == NULL)
        {
            return NVAPI_OUT_OF_MEMORY;
        }
        // Allocate the target details
        memset(pathInfo[i].targetInfo, 0, pathInfo[i].targetInfoCount * sizeof(NV_DISPLAYCONFIG_PATH_TARGET_INFO));
        for (NvU32 j = 0 ; j < pathInfo[i].targetInfoCount ; j++)
        {
            pathInfo[i].targetInfo[j].details = (NV_DISPLAYCONFIG_PATH_ADVANCED_TARGET_INFO*) malloc(sizeof(NV_DISPLAYCONFIG_PATH_ADVANCED_TARGET_INFO));    
            memset(pathInfo[i].targetInfo[j].details, 0, sizeof(NV_DISPLAYCONFIG_PATH_ADVANCED_TARGET_INFO));
            pathInfo[i].targetInfo[j].details->version = NV_DISPLAYCONFIG_PATH_ADVANCED_TARGET_INFO_VER;
        }
    }

    // Retrieve the full path info
    ret = NvAPI_DISP_GetDisplayConfig(&pathCount, pathInfo);
    if (ret != NVAPI_OK)    
    {
        return ret;
    }

    *pathInfoCount = pathCount;
    *pPathInfo = pathInfo;
    return NVAPI_OK;
}

现在可以像以下一样轻松使用此功能：

NV_DISPLAYCONFIG_PATH_INFO *pathInfo = NULL;
NvU32 pathCount = 0;
_allocateAndGetDisplayConfig(&pathCount, &pathInfo);
// Do whatever you need with the queried display data here

如何使用NvAPI_DISP_GetDisplayConfig？

3 个答案: