From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755466AbaFWVUh (ORCPT ); Mon, 23 Jun 2014 17:20:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51436 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754424AbaFWVUg (ORCPT ); Mon, 23 Jun 2014 17:20:36 -0400 Message-ID: <1403558424.755.58.camel@deneb.redhat.com> Subject: Re: [PATCH 2/3] efi/reboot: Allow powering off machines using EFI From: Mark Salter To: Matt Fleming Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Alan Cox , "H. Peter Anvin" , Aubrey Li , Matt Fleming Date: Mon, 23 Jun 2014 17:20:24 -0400 In-Reply-To: <1403185225-9031-3-git-send-email-matt@console-pimps.org> References: <1403185225-9031-1-git-send-email-matt@console-pimps.org> <1403185225-9031-3-git-send-email-matt@console-pimps.org> Organization: Red Hat, Inc Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-06-19 at 14:40 +0100, Matt Fleming wrote: > From: Matt Fleming > > Not only can EfiResetSystem() be used to reboot, it can also be used to > power down machines. > > By and large, this functionality doesn't work very well across the range > of EFI machines in the wild, so it should definitely only be used as a > last resort. In an ideal world, this wouldn't be needed at all. > > Unfortunately, we're starting to see machines where EFI is the *only* > reliable way to power down, and nothing else, not PCI, not ACPI, works. > > efi_poweroff_required() should be implemented on a per-architecture > basis, since exactly when we should be using EFI runtime services is a > platform-specific decision. There's no analogue for reboot because each > architecture handles reboot very differently - the x86 code in > particular is pretty complex. > > Patches to enable this for specific classes of hardware will be > submitted separately. > > Cc: Mark Salter > Signed-off-by: Matt Fleming > --- Tested-by: Mark Salter