From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH v8 08/21] dt / chosen: Add linux,uefi-stub-generated-dtb property Date: Sat, 07 Feb 2015 11:36:42 +0800 Message-ID: <54D5884A.6050009@linaro.org> References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-9-git-send-email-hanjun.guo@linaro.org> <20150202134033.GR4278@bivouac.eciton.net> <20150202135051.GA3825@xora-haswell.xora.org.uk> <20150202163253.GG21175@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:51352 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751899AbbBGDgx (ORCPT ); Fri, 6 Feb 2015 22:36:53 -0500 Received: by mail-pa0-f46.google.com with SMTP id lj1so21237582pab.5 for ; Fri, 06 Feb 2015 19:36:53 -0800 (PST) In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: G Gregory , Mark Rutland , Leif Lindholm Cc: Catalin Marinas , "Rafael J. Wysocki" , Olof Johansson , Arnd Bergmann , "grant.likely@linaro.org" , Will Deacon , Lorenzo Pieralisi , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , Ashwin Chaugule , "suravee.suthikulpanit@amd.com" On 2015=E5=B9=B402=E6=9C=8806=E6=97=A5 18:34, G Gregory wrote: [...] >>>>> ---------------------------------------------------------------= ----------------- >>>>> linux,uefi-stub-kern-ver | string | Copy of linux_banner from = build. >>>>> ---------------------------------------------------------------= ----------------- >>>>> +linux,uefi-stub-generated-dtb | bool | Indication for no DTB pr= ovided by >>>>> + | | firmware. >>>>> +----------------------------------------------------------------= ---------------- >>>> >>>> Apologies for the late bikeshedding, but the discussion on this to= pic >>>> previsously was lively enough that I thought I'd let it die down a= bit >>>> before seeing if I had anything to add. >>>> >>>> That, and I just realised something: >>>> One alternative to this added DT entry is that we could treat the >>>> absence of a registered UEFI configuration table as the indication >>>> that no HW description was provided from firmware, since the stub = does >>>> not call InstallConfigurationTable() on the DT it generates. This = does >>>> move the ability to detect to after efi_init(), but this should be >>>> fine for ACPI-purposes. >>>> >>> That would not work as expected in the kexec/Xen use case though as= they >>> may genuinely boot with DT from an ACPI host without UEFI. >> >> I'm a little concerned by this case. How do we intend to pass stuff = from >> Xen to the kernel in this case? When we initially discussed the stub >> prior to merging, we weren't quite sure if ACPI without UEFI was >> entirely safe. >> >> The linux,uefi-stub-kern-ver property was originally intended as a >> sanity-check feature to ensure nothing (including Xen) masqueraded a= s >> the stub, but for some reason the actual sanity check was never >> implemented. >> >>>> If that is deemed undesirable, I would still prefer Catalin's >>>> suggested name ("linux,bare-dtb"), which describes the state rathe= r >>>> than the route we took to get there. >>>> >>> I agree. >> >> I guess this would be ok, though it would be nice to know which agen= t >> generated the DTB. >> > > The most obvious scheme then is > > linux,bare-dtb =3D "uefi-stub"; > > otherwise we generate a new binding for every component in the boot p= ath. Leif, Mark, any comments on this? 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