problems when clone the pixman

[Daniel-bboy]

Hello, I have always met the problem when I "git submodule update --init --recursive".
Cloning into 'pixman'...
fatal: unable to connect to anongit.freedesktop.org:
anongit.freedesktop.org[0: 131.252.210.161]: errno=Connection timed out

fatal: clone of 'git://anongit.freedesktop.org/pixman' into submodule path 'pixman' failed
Failed to recurse into submodule path 'rocket-chip/riscv-tools/riscv-gnu-toolchain/riscv-qemu'
Failed to recurse into submodule path 'rocket-chip/riscv-tools/riscv-gnu-toolchain'
Failed to recurse into submodule path 'rocket-chip/riscv-tools'
Failed to recurse into submodule path 'rocket-chip'

I have tried many times but nothing change. Is there any method to solve the problem? Thank you.