[gentoo-user] failed to setup uefi boot

[Wankey Cheng]

Hi,Everyone:
         I am a new user of gentoo,I encounter an error of the "efibootmgr
-c -d /dev/sda -p 1 -L Gentoo -l "\efi\boot\bootx64.efi" " command.When I
execute it ,I got
Failed to write variable:No space left on device
Failed to write variable:Input/Output error

what's wrong with it？how can I fix it？

my kernel version is 3.8.13,and all config need by efi has enabled.