最近准备学习一下用yocto来开发linux，在网站上面下载了手册，按手册里面装好了环境，可以在使用bitbake进行编译的时候，总是提示有些软件包无法下载，使用来代理和VPN来下载也还是会有很多的不能下载，希望有这方面经验帮忙给看看：
NOTE: Preparing runqueue
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
WARNING: Failed to fetch URL git://git.freescale.com/imx/uboot-imx.git;protocol=git;branch=imx_v2014.04_3.14.28_1.0.0_ga, attempting MIRRORS if available
WARNING: Failed to fetch URL git://github.com/Itseez/opencv.git;branch=2.4, attempting MIRRORS if available
ERROR: Fetcher failure: Fetch command failed with exit code 128, output:
Cloning into bare repository '/opt/freescale/fsl-release-bsp/fsl-yocto-3.14.28-1.0.0/downloads//git2/git.freescale.com.imx.uboot-imx.git'...
fatal: unable to connect to git.freescale.com:
git.freescale.com: Name or service not known
ERROR: Function failed: Fetcher failure for URL: 'git://git.freescale.com/imx/uboot-imx.git;protocol=git;branch=imx_v2014.04_3.14.28_1.0.0_ga'. Unable to fetch URL from any source.
ERROR: Logfile of failure stored in: /opt/freescale/fsl-release-bsp/fsl-yocto-3.14.28-1.0.0/build-imx6qsabresd-x11-qt5/tmp/work/imx6qsabresd-poky-linux-gnueabi/u-boot-imx/2014.04-r0/temp/log.do_fetch.2951
ERROR: Task 36 (/opt/freescale/fsl-release-bsp/fsl-yocto-3.14.28-1.0.0/sources/meta-fsl-bsp-release/imx/meta-fsl-arm/recipes-bsp/u-boot/u-boot-imx_2014.04.bb, do_fetch) failed with exit code '1'
WARNING: Failed to fetch URL http://ftp.de.debian.org/debian/pool/main/m/mklibs/mklibs_0.1.39.tar.xz, attempting MIRRORS if available
