From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53104) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aJO6V-0000oy-GJ for qemu-devel@nongnu.org; Wed, 13 Jan 2016 11:17:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aJO6R-0004jD-J4 for qemu-devel@nongnu.org; Wed, 13 Jan 2016 11:16:59 -0500 Date: Wed, 13 Jan 2016 17:16:41 +0100 From: Andrew Jones Message-ID: <20160113161641.GC10709@hawk.localdomain> References: <1452696857-4091-1-git-send-email-shannon.zhao@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452696857-4091-1-git-send-email-shannon.zhao@linaro.org> Subject: Re: [Qemu-devel] [PATCH v2] ARM: Virt: Don't generate RTC ACPI device when using UEFI List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Shannon Zhao Cc: peter.maydell@linaro.org, ard.biesheuvel@linaro.org, edk2-devel@ml01.01.org, qemu-devel@nongnu.org, qemu-arm@nongnu.org, zhaoshenglong@huawei.com, lersek@redhat.com On Wed, Jan 13, 2016 at 10:54:17PM +0800, Shannon Zhao wrote: > When booting the VM with UEFI, UEFI takes ownership of the RTC hardware. > While UEFI can use libfdt to disable the RTC device node in the DTB that > it passes to the OS, it cannot modify AML. Therefore, we won't generate > the RTC ACPI device at all when using UEFI. I think a condensed comment similar to this commit message would be nice in build_dsdt, or somewhere. We have a policy for mach-virt of generating ACPI for everything we generate DT. It'd be good if we documented all the divergences in order to avoid confusion. I won't insist though. Thanks, drew