From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56575) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZNL4s-0006PK-2v for qemu-devel@nongnu.org; Thu, 06 Aug 2015 09:19:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZNL4o-0001yW-OQ for qemu-devel@nongnu.org; Thu, 06 Aug 2015 09:19:22 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:33947) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZNL4o-0001y9-IC for qemu-devel@nongnu.org; Thu, 06 Aug 2015 09:19:18 -0400 Received: by pawu10 with SMTP id u10so63123657paw.1 for ; Thu, 06 Aug 2015 06:19:17 -0700 (PDT) Message-ID: <55C35ECD.6040704@linaro.org> Date: Thu, 06 Aug 2015 21:19:09 +0800 From: Shannon Zhao MIME-Version: 1.0 References: <1438860267-3401-1-git-send-email-leif.lindholm@linaro.org> <20150806122803.GA3083@hawk.localdomain> In-Reply-To: <20150806122803.GA3083@hawk.localdomain> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] hw/arm/virt-acpi-build: drop _ADR entry from SPCR List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrew Jones , Leif Lindholm Cc: qemu-devel@nongnu.org On 2015/8/6 20:28, Andrew Jones wrote: > On Thu, Aug 06, 2015 at 12:24:27PM +0100, Leif Lindholm wrote: >> >The _ADR entry in SPCR is optional and redundant. The same information >> >is already provided in _CRS (which is mandatory). >> > >> >Signed-off-by: Leif Lindholm >> >--- >> > >> >So, this _ADR entry is only consumed by a set of not-widely-circulated >> >patches for the Linux kernel. And while the ARM Server Base Boot >> >Requirements specification mandates SPCR, it does not mandate this _ADR >> >entry. >> > >> >In the interest of not propagating non-standard extensions, I would be >> >really happy if we could consider dropping this from 2.4. >> >I do realize that this is a completely unreasonable request this late >> >in the release process, but I only spotted this yesterday, and it is a >> >very isolated change with very quantifiable effects. >> > >> >The patch athttps://git.linaro.org/leg/acpi/leg-kernel.git/commitdiff/46eeec7b7332bdd104941703696d3812afd934c8 >> >converts the non-upstream kernel SPCR handling code to use the _CRS >> >information instead. > Grr... So when I saw how the kernel (the original non-upstream patch) > was using ADR, I presumed that that was a documented behavior. I guess > I should have confirmed that... > > While the kernel change makes sense, I'm not sure we want this QEMU > patch, as there*are* kernels already using ADR. In the least I wouldn't > want to get burned twice, so I'd prefer to see the SPCR code actually > get into Linux first this time. That would also allow us to point at > something when we start breaking guests. I agree. It would be better after the kernel patch get into upstream kernel. > Actually, why was ADR used > the first time? It would be good to know the story there in case there > as a valid reason. -- Shannon