debian wheezy freezing unless mouse move/click

/etc/default/grub ...

Test -
GRUB_CMDLINE_LINUX_DEFAULT="quiet pci=nommconf idle=poll"
- failed!

Test -
GRUB_CMDLINE_LINUX_DEFAULT="quiet nolapic_timer clocksource=jiffies"
- failed!

Test -
GRUB_CMDLINE_LINUX_DEFAULT="quiet nohz=off"

- works!