Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758768AbYFBMOP (ORCPT ); Mon, 2 Jun 2008 08:14:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752986AbYFBMOB (ORCPT ); Mon, 2 Jun 2008 08:14:01 -0400 Received: from mx1.redhat.com ([66.187.233.31]:47888 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752649AbYFBMOA (ORCPT ); Mon, 2 Jun 2008 08:14:00 -0400 To: Ingo Molnar Cc: Jeremy Fitzhardinge , "Rafael J. Wysocki" , Thomas Gleixner , xen-devel , LKML Subject: Re: [Xen-devel] Re: [PATCH 08 of 12] xen-console: add save/restore References: <20080602111720.GC18586@elte.hu> From: Markus Armbruster Date: Mon, 02 Jun 2008 14:13:19 +0200 In-Reply-To: <20080602111720.GC18586@elte.hu> (Ingo Molnar's message of "Mon\, 2 Jun 2008 13\:17\:20 +0200") Message-ID: <87ve0shw68.fsf@pike.pond.sub.org> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2562 Lines: 60 Ingo Molnar writes: > -tip testing found the following xen-console symbols trouble: > > ERROR: "console_drivers" [drivers/video/xen-fbfront.ko] undefined! > ERROR: "get_phys_to_machine" [drivers/video/xen-fbfront.ko] undefined! > ERROR: "get_phys_to_machine" [drivers/net/xen-netfront.ko] undefined! > ERROR: "get_phys_to_machine" [drivers/input/xen-kbdfront.ko] undefined! > > with: > > http://redhat.com/~mingo/misc/config-Mon_Jun__2_12_26_38_CEST_2008.bad > > get_phys_to_machine can indeed be exported but i'm less sure about the > console_drivers export ... The temporary fix below resolves it for now. > > Ingo xen-fbfront makes itself the preferred console when it is actually enabled. It does that by re-registering itself with CON_CONSDEV set, and for that it needs to find its struct console. Simple, works. Perhaps you can think of a better solution for this problem. I'm all ears! Details are in this commit: xen: Enable console tty by default in domU if it's not a dummy Without console= arguments on the kernel command line, the first console to register becomes enabled and the preferred console (the one behind /dev/console). This is normally tty (assuming CONFIG_VT_CONSOLE is enabled, which it commonly is). This is okay as long tty is a useful console. But unless we have the PV framebuffer, and it is enabled for this domain, tty0 in domU is merely a dummy. In that case, we want the preferred console to be the Xen console hvc0, and we want it without having to fiddle with the kernel command line. Commit b8c2d3dfbc117dff26058fbac316b8acfc2cb5f7 did that for us. Since we now have the PV framebuffer, we want to enable and prefer tty again, but only when PVFB is enabled. But even then we still want to enable the Xen console as well. Problem: when tty registers, we can't yet know whether the PVFB is enabled. By the time we can know (xenstore is up), the console setup game is over. Solution: enable console tty by default, but keep hvc as the preferred console. Change the preferred console to tty when PVFB probes successfully, unless we've been given console kernel parameters. Signed-off-by: Markus Armbruster [...] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/