From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v5 1/5] ACPI: introduce CONFIG_ACPI_REDUCED_HARDWARE_ONLY to enforce this ACPI mode Date: Wed, 8 Jan 2014 13:46:25 +0100 Message-ID: <201401081346.25767.arnd@arndb.de> References: <1389142011-27356-1-git-send-email-al.stone@linaro.org> <1389142011-27356-2-git-send-email-al.stone@linaro.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.8]:57871 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756252AbaAHMqg (ORCPT ); Wed, 8 Jan 2014 07:46:36 -0500 In-Reply-To: <1389142011-27356-2-git-send-email-al.stone@linaro.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: al.stone@linaro.org, linux-acpi@vger.kernel.org, Hanjun Guo , patches@linaro.org, linaro-kernel@lists.linaro.org, linaro-acpi@lists.linaro.org On Wednesday 08 January 2014, al.stone@linaro.org wrote: > Even though support for X86 in hardware reduced mode is possible, it > is NOT enabled. Extensive effort has gone into the Linux kernel so that > there is a single kernel image than can run on all x86 hardware; the kernel > changes run-time behavior to adapt to the hardware being used. This is not > currently possible with the existing ACPICA infrastructure but only presents > a problem on achitectures supporting both hardware-reduced and legacy modes > of ACPI -- i.e., on x86 only. Not sure about the logic here: While it's certainly possible to build a kernel that runs on all x86 machines, it's also possible to build one that only runs on some of them when some basic options are turned off. I don't see any difference between that and what we have on ARM64 or the multiplatform subset of ARM32. I don't think you need any strict architecture dependency here. If you want to make it harder for users to accidentally turn it on, I'd suggest using config ACPI_REDUCED_HARDWARE_ONLY bool "Hardware-reduced ACPI support only" depends on !X86 || EXPERT Arnd