From owner-freebsd-arch@FreeBSD.ORG Sun Jan 4 06:37:05 2015 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id A1841952 for ; Sun, 4 Jan 2015 06:37:05 +0000 (UTC) Received: from mail-wg0-x22b.google.com (mail-wg0-x22b.google.com [IPv6:2a00:1450:400c:c00::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 344F93FDB for ; Sun, 4 Jan 2015 06:37:05 +0000 (UTC) Received: by mail-wg0-f43.google.com with SMTP id k14so8080726wgh.30 for ; Sat, 03 Jan 2015 22:37:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=5EoC/tONEqiPrt9TT6lFIKsmSBhZMTL6jYAxSiiyL+U=; b=pr2o2xVGRnzFK0FOqew2M+ycrdG8faZ0agNntoAVYFLm1lFSmff4xMs5WBrMRpUmhM eaXYYOAkTTeZGGfHGDLhUwc7awwUeK56eOsG4u9ren0RjB6WaN1u+jL18LohQy18BIdG 4xq1JdRdUxYcHNEmxOxe7Z2s3XG0ZDnPDthAhwHmX/IZ/rvsUzrzuUl5h4eoxBU7faqK KQfmu9Bavd24YGTESGxGiLyxBBnYINleao5x1EmkFuLFK3qAUPG5K/gCUcYi6adJsNJ5 TLDHKrtd34L4dZCo9KcBUSLwboZkfx8yofEqVlTn2Oe8K9rJ/SAufODQM0qZE8lcOPoD zJZw== MIME-Version: 1.0 X-Received: by 10.194.24.103 with SMTP id t7mr167460272wjf.15.1420353423660; Sat, 03 Jan 2015 22:37:03 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.216.41.136 with HTTP; Sat, 3 Jan 2015 22:37:03 -0800 (PST) In-Reply-To: <2F715AD9-CF34-4516-B75E-E14C77BFD2E3@mu.org> References: <2F715AD9-CF34-4516-B75E-E14C77BFD2E3@mu.org> Date: Sat, 3 Jan 2015 22:37:03 -0800 X-Google-Sender-Auth: RXlEUX_w2jGLXTqtxqD6pfxm5dg Message-ID: Subject: Re: odd behaviour with graphics, vt(4), VGA, and probing the text region leading to NMIs at boot From: Adrian Chadd To: Alfred Perlstein Content-Type: text/plain; charset=UTF-8 Cc: "freebsd-arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 04 Jan 2015 06:37:05 -0000 On 3 January 2015 at 09:31, Alfred Perlstein wrote: > Sounds like the virtualization code is sensitive to the mode. Meaning that whatever is virtualizing the graphics card doesn't do the proper thing when you're in a graphical mode. Can't the probes be turned off? So it's happening quite late in the boot process - when the ISA bus is being probed. So, maybe we can just avoid probing the dev/vga stuff like this. I'll have to talk to Ed/ray about how the syscons and vt devices hold together. I'm kinda shocked that we're re-probing things via an ISA probe so late in the boot process. > Basically when the "card" is in gfx mode, it doesn't do the right thing for those memory addresses. Sounds like the fix would be to not touch those regions unless you're actually in text mode. -adrian