织梦做双语版网站,wordpress赞的功能,wordpress模板二次开发,网站宣传策划方案接前一篇文章#xff1a;libdrm全解析三十九 —— 源码全解析#xff08;36#xff09; 本文参考以下博文#xff1a;
DRM 驱动程序开发#xff08;VKMS#xff09;
特此致谢#xff01; 前一篇文章讲解完了资源的释放流程中的munmap()和drmIoctl(DRM_IOCTL_MODE_DEST…接前一篇文章libdrm全解析三十九 —— 源码全解析36 本文参考以下博文
DRM 驱动程序开发VKMS
特此致谢 前一篇文章讲解完了资源的释放流程中的munmap()和drmIoctl(DRM_IOCTL_MODE_DESTROY_DUMB)本回讲解drmModeFreeConnector函数。drmModeFreeConnector()与drmModeGetConnector()是一对。
drmModeFreeConnector函数在xf86drmMode.c中代码如下
drm_public void drmModeFreeConnector(drmModeConnectorPtr ptr)
{if (!ptr)return;drmFree(ptr-encoders);drmFree(ptr-prop_values);drmFree(ptr-props);drmFree(ptr-modes);drmFree(ptr);
}
可见drmModeFreeConnector函数并没有想象中与之专门对应的DRM_IOCTL_MODE_FREE_CONNECTOR宏而是调用了drmFree函数释放了多个分配的空间。
前文讲过drmFree函数在xf86drm.c中代码如下
drm_public void drmFree(void *pt)
{free(pt);
}
就是free函数的简单封装。
drmModeFreeConnector函数的作用是释放drmModeGetConnector函数中分配的各个空间。
为了便于理解再次贴出drmModeGetConnector函数代码在xf86drmMode.c中如下
/** Connector manipulation*/
static drmModeConnectorPtr
_drmModeGetConnector(int fd, uint32_t connector_id, int probe)
{struct drm_mode_get_connector conn, counts;drmModeConnectorPtr r NULL;struct drm_mode_modeinfo stack_mode;memclear(conn);conn.connector_id connector_id;if (!probe) {conn.count_modes 1;conn.modes_ptr VOID2U64(stack_mode);}if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, conn))return 0;retry:counts conn;if (conn.count_props) {conn.props_ptr VOID2U64(drmMalloc(conn.count_props*sizeof(uint32_t)));if (!conn.props_ptr)goto err_allocs;conn.prop_values_ptr VOID2U64(drmMalloc(conn.count_props*sizeof(uint64_t)));if (!conn.prop_values_ptr)goto err_allocs;}if (conn.count_modes) {conn.modes_ptr VOID2U64(drmMalloc(conn.count_modes*sizeof(struct drm_mode_modeinfo)));if (!conn.modes_ptr)goto err_allocs;} else {conn.count_modes 1;conn.modes_ptr VOID2U64(stack_mode);}if (conn.count_encoders) {conn.encoders_ptr VOID2U64(drmMalloc(conn.count_encoders*sizeof(uint32_t)));if (!conn.encoders_ptr)goto err_allocs;}if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, conn))goto err_allocs;/* The number of available connectors and etc may have changed with a* hotplug event in between the ioctls, in which case the field is* silently ignored by the kernel.*/if (counts.count_props conn.count_props ||counts.count_modes conn.count_modes ||counts.count_encoders conn.count_encoders) {drmFree(U642VOID(conn.props_ptr));drmFree(U642VOID(conn.prop_values_ptr));if (U642VOID(conn.modes_ptr) ! stack_mode)drmFree(U642VOID(conn.modes_ptr));drmFree(U642VOID(conn.encoders_ptr));goto retry;}if(!(r drmMalloc(sizeof(*r)))) {goto err_allocs;}r-connector_id conn.connector_id;r-encoder_id conn.encoder_id;r-connection conn.connection;r-mmWidth conn.mm_width;r-mmHeight conn.mm_height;/* convert subpixel from kernel to userspace */r-subpixel conn.subpixel 1;r-count_modes conn.count_modes;r-count_props conn.count_props;r-props drmAllocCpy(U642VOID(conn.props_ptr), conn.count_props, sizeof(uint32_t));r-prop_values drmAllocCpy(U642VOID(conn.prop_values_ptr), conn.count_props, sizeof(uint64_t));r-modes drmAllocCpy(U642VOID(conn.modes_ptr), conn.count_modes, sizeof(struct drm_mode_modeinfo));r-count_encoders conn.count_encoders;r-encoders drmAllocCpy(U642VOID(conn.encoders_ptr), conn.count_encoders, sizeof(uint32_t));r-connector_type conn.connector_type;r-connector_type_id conn.connector_type_id;if ((r-count_props !r-props) ||(r-count_props !r-prop_values) ||(r-count_modes !r-modes) ||(r-count_encoders !r-encoders)) {drmFree(r-props);drmFree(r-prop_values);drmFree(r-modes);drmFree(r-encoders);drmFree(r);r 0;}err_allocs:drmFree(U642VOID(conn.prop_values_ptr));drmFree(U642VOID(conn.props_ptr));if (U642VOID(conn.modes_ptr) ! stack_mode)drmFree(U642VOID(conn.modes_ptr));drmFree(U642VOID(conn.encoders_ptr));return r;
}
资源释放流程中的其余函数将在后续文章中进行解析。
