Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752682Ab0HBVfV (ORCPT ); Mon, 2 Aug 2010 17:35:21 -0400 Received: from mail1-out1.atlantis.sk ([80.94.52.55]:56156 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751255Ab0HBVfU (ORCPT ); Mon, 2 Aug 2010 17:35:20 -0400 From: Ondrej Zary To: "H. Peter Anvin" Subject: Re: 6175ddf06b6172046a329e3abfd9c901a43efd2e breaks matroxfb console Date: Mon, 2 Aug 2010 23:35:10 +0200 User-Agent: KMail/1.9.10 Cc: brgerst@gmail.com, Kernel development list References: <201008022150.01037.linux@rainbow-software.org> <201008022314.26743.linux@rainbow-software.org> <4C573575.8040701@zytor.com> In-Reply-To: <4C573575.8040701@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201008022335.12191.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2513 Lines: 59 On Monday 02 August 2010 23:15:33 H. Peter Anvin wrote: > On 08/02/2010 02:14 PM, Ondrej Zary wrote: > > On Monday 02 August 2010 23:04:28 H. Peter Anvin wrote: > >> On 08/02/2010 12:49 PM, Ondrej Zary wrote: > >>> Hello, > >>> matroxfb (at least with Mystique and Mystique 220) stopped working in > >>> 2.6.34 - the screen is completely corrupted. Bisection shows that > >>> 6175ddf06b6172046a329e3abfd9c901a43efd2e is first bad commit. > >>> > >>> Reverting 6175ddf06b6172046a329e3abfd9c901a43efd2e in 2.6.34 fixes the > >>> problem (1c5b9069e12e20d2fe883076ae0bf73966492108 must be reverted > >>> first). > >> > >> Sounds like another driver which used memcpy_toio() when it should have > >> used iowrite32_rep() or __iowrite32_copy(). > >> > >> Hmm... is __iowrite32_copy() and iowrite32_rep() redundant? If so, we > >> should get rid of the former. > > > > There is a wrapper in drivers/video/matrox/matroxfb_base.h (see below) > > with some comment. So this commit changed one of the three points? > > > > static inline void mga_memcpy_toio(vaddr_t va, const void* src, int len) > > { #if defined(__alpha__) || defined(__i386__) || defined(__x86_64__) /* > > * memcpy_toio works for us if: > > * (1) Copies data as 32bit quantities, not byte after byte, > > * (2) Performs LE ordered stores, and > > * (3) It copes with unaligned source (destination is guaranteed > > to be page * aligned and length is guaranteed to be multiple of 4). > > */ > > memcpy_toio(va.vaddr, src, len); > > #else > > Yes, point (1) is not guaranteed by memcpy_toio(). Now I wonder how many drivers will this break... The patch below fixes it for me. Is it correct on all architectures? --- linux-2.6.35-rc2/drivers/video/matrox/matroxfb_base.h 2010-06-06 05:43:24.000000000 +0200 +++ linux-2.6.35-rc3/drivers/video/matrox/matroxfb_base.h 2010-08-02 23:31:34.000000000 +0200 @@ -157,7 +157,7 @@ static inline void mga_memcpy_toio(vaddr * (3) It copes with unaligned source (destination is guaranteed to be page * aligned and length is guaranteed to be multiple of 4). */ - memcpy_toio(va.vaddr, src, len); + iowrite32_rep(va.vaddr, src, len); #else u_int32_t __iomem* addr = va.vaddr; -- Ondrej Zary -- 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/