From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH v5 18/18] Documentation: ACPI for ARM64 Date: Sun, 04 Jan 2015 17:39:24 +0800 Message-ID: <54A90A4C.60908@linaro.org> References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-19-git-send-email-hanjun.guo@linaro.org> <20141224171815.GD13399@e104818-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:62427 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750921AbbADJjq (ORCPT ); Sun, 4 Jan 2015 04:39:46 -0500 Received: by mail-pa0-f54.google.com with SMTP id fb1so26740058pad.13 for ; Sun, 04 Jan 2015 01:39:46 -0800 (PST) In-Reply-To: <20141224171815.GD13399@e104818-lin.cambridge.arm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Catalin Marinas Cc: "Rafael J. Wysocki" , Mark Rutland , Olof Johansson , "grant.likely@linaro.org" , Will Deacon , "graeme.gregory@linaro.org" , Arnd Bergmann , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Lv Zheng , Robert Moore , Lorenzo Pieralisi , Liviu Dudau , Randy Dunlap , Charles Garcia-Tobin , Kangkang.Shen@huawe On 2014=E5=B9=B412=E6=9C=8825=E6=97=A5 01:18, Catalin Marinas wrote: [...] > > In addition to the above and _DSD requirements/banning, I would also = add > some clear statements around: > > _OSC: only global/published capabilities are allowed. For > device-specific _OSC we need a process or maybe we can ban them entir= ely > and rely on _DSD once we clarify the process. > > _OSI: firmware must not check for certain _OSI strings. Here I'm not > sure what we would have to do for ARM Linux. Reporting "Windows" does > not make any sense but not reporting anything can, as Matthew Garrett > pointed out, can be interpreted by firmware as "Linux". In addition t= o > any statements in this document, I suggest you patch > drivers/acpi/acpica/utosi.c accordingly, maybe report "Linux" for ARM > and print a kernel warning so that we notice earlier. > > ACPI_OS_NAME: this is globally defined as "Microsoft Windows NT". It > doesn't make much sense in the ARM context. Could we change it to > "Linux" when CONFIG_ARM64? We will work on this both on ASWG and linux ACPI driver side, as Dong and Charles pointed out, _OSI things can be solved in ACPI spec, when that is done, we can modify the kernel driver to fix the problems above= =2E > > Compatibility with older kernels: ACPI firmware must work, even thoug= h > not fully optimal, with the earliest kernel version implementing the > targeted ACPI spec. There may be a need for new drivers but otherwise > adding things like CPU power management should not break older kernel > versions. In addition, the ACPI firmware must also work with the late= st > kernel version. It should be, and I think that's why we need ACPI (or DT) here :) Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html