From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756928AbZF3Pol (ORCPT ); Tue, 30 Jun 2009 11:44:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753912AbZF3PoW (ORCPT ); Tue, 30 Jun 2009 11:44:22 -0400 Received: from kroah.org ([198.145.64.141]:58384 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006AbZF3PoT (ORCPT ); Tue, 30 Jun 2009 11:44:19 -0400 Date: Tue, 30 Jun 2009 08:43:36 -0700 From: Greg KH To: Marc Aurele La France Cc: hpa@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org, "H. Peter Anvin" , Research.Support@ualberta.ca Subject: Re: [rs] Re: [stable] [PATCH] x86, setup (2.6.30-stable) fix 80x34 and 80x60 console modes Message-ID: <20090630154336.GE16038@kroah.com> References: <4A496A0C.809@kernel.org> <20090630034822.GC12373@kroah.com> <4A49B1C6.9040900@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 30, 2009 at 08:01:47AM -0600, Marc Aurele La France wrote: > On Mon, 29 Jun 2009, H. Peter Anvin wrote: > > Greg KH wrote: > >> On Mon, Jun 29, 2009 at 06:27:40PM -0700, H. Peter Anvin wrote: > >>> Marc Aurele La France wrote: > >>>> As coded, most INT10 calls in video-vga.c allow the compiler to assume EAX > >>>> remains unchanged across them, which is not always the case. This > >>>> triggers an optimisation issue that causes vga_set_vertical_end() to be > >>>> called with an incorrect number of scanlines. Fix this by beefing up the > >>>> asm constraints on these calls. > > >>>> Reported-by: Marc Aurele La France > >>>> Signed-off-by: Marc Aurele La France > >>>> Acked-by: H. Peter Anvin > > >>> Note: this is not in upstream since upstream is not affected due to the > >>> new "BIOS glovebox" subsystem. > > >> So it is a ".30 only" type patch? Any older kernel versions affected? > > > Yes, all the way back to .23 or something like that. > > No. The problem can only arise in 2.6.30 and is a consequence of commit > 5f641356127712fbdce0eee120e5ce115860c17f. It disappears with subsequent > mainline commit cf06de7b9cdd3efee7a59dced1977b3c21d43732. > > Prior to 2.6.30, vga_set_480_scanlines() was passed a byte-size value (as > an int), which means the compiler was forced to load EAX, instead of only > AL, even if it did assume AH still contained 0x01. That 0x01 is what the > last INT10 call in the vga_set_{8,14}font() functions sets AH to. > > In truth, only those two INT10's need beefing up. But I did them all for > completeness. Ah, thanks. Next time, putting that information into the patch itself would be most helpful :) I'll go queue it up. greg k-h