Hi, I've been fiddling around with this for a while. Booting with init=/bin/bash allowed poweroff -f to work. So I then booted into full userspace and started to rip modules out with rmmod.
It appears that the laptop has a Synopsys DesignWare controller embedded in it. This makes the kernel load the dw_dmac_core and dw_dmac modules. An rmmod of dw_dmac produces an instant lockup. I think it is the same lockup happening at shutdown and reboot. Blacklisting both modules makes shutdown and reboot work correctly for me. I suspect that some sort of DMI based blacklist will be required in the kernel. Exposing the hardware to user space probably isn't the best idea anyway. Cheers, Scott ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1319149 Title: [HP Pavilion 11-n038ca x360 PC] Boots very unreliably To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1319149/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs