Re: [PATCH] x86: Add reboot quirk for Dell Precision M4600

Matthew Garrett
2011-08-06T15:30:22Z

On Sat, Aug 06, 2011 at 08:56:35AM +0200, Ingo Molnar wrote:
> Weird - ACPI is the default Windows method of reboot - how come it
> does not work on that box? Does Windows work around this specific
> machine (unlikely), or is our ACPI boot sequence not 100% compatible
> with the Windows method (more likely IMO)?

The ACPI reboot method on these machines hits the keyboard controller
rather than PCI, which is unusual. What I suspect is that the write
triggers some SMM or EC code that's making assumptions about system
state, and we're not quite identical. Bouncing on the keyboard
controller from userspace with init=/bin/bash wedges in the same way.

--
Matthew Garrett | mjg59@srcf.ucam.org