Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752703AbaF3M0D (ORCPT ); Mon, 30 Jun 2014 08:26:03 -0400 Received: from mail-ve0-f179.google.com ([209.85.128.179]:59714 "EHLO mail-ve0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750831AbaF3M0B (ORCPT ); Mon, 30 Jun 2014 08:26:01 -0400 MIME-Version: 1.0 In-Reply-To: <53B14E9E.3040505@vmware.com> References: <1395967502-71219-1-git-send-email-chrisfriedt@gmail.com> <533A8E52.5050304@vmware.com> <53B14E9E.3040505@vmware.com> From: Christopher Friedt Date: Mon, 30 Jun 2014 08:25:40 -0400 Message-ID: Subject: Re: [PATCH 1/1] drm/vmwgfx: correct fb_fix_screeninfo.line_length To: Thomas Hellstrom Cc: dri-devel , linux-kernel@vger.kernel.org, Dave Airlie , linux-graphics-maintainer@vmware.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 30, 2014 at 7:48 AM, Thomas Hellstrom wrote: > I don't think we can blame video-vmware for this. A kernel driver change > that breaks existing user-space is by definition a kernel driver bug, > regardless whether exisiting user-space is doing something horrendously > stupid. I wouldn't be so quick to say it's a kernel bug. The fbdev contract hasn't changed. Also xf86-video-vmware isn't using the fbdev driver, and the fbdev driver code is obviously correct (see screenshots in link submitted with initial patch). > So the fix must IMO be a kernel driver fix. My initial guess is that > once we set the bytes per line register, it might not be automatically > updated when the screen width is changed, but the documentation is poor. > I see if I can shed some light over this. Having dumped all of the svga registers while hacking on vmwgfx, I noticed that the BYTES_PER_LINE field is initially incorrectly set to something way off. My initial reaction is that video-vmware doesn't properly compute the bytes-per-line register, and therefore that it is a video-vmware bug that has always existed. I'm reproducing the problem and providing a fix for video-vmware as I write this. C -- 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/