From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932070AbYDVPy1 (ORCPT ); Tue, 22 Apr 2008 11:54:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756195AbYDVPyT (ORCPT ); Tue, 22 Apr 2008 11:54:19 -0400 Received: from mtagate1.uk.ibm.com ([195.212.29.134]:61292 "EHLO mtagate1.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756112AbYDVPyS (ORCPT ); Tue, 22 Apr 2008 11:54:18 -0400 Message-ID: <480E0A54.9010203@linux.vnet.ibm.com> Date: Tue, 22 Apr 2008 17:55:00 +0200 From: Christian Ehrhardt Organization: =?ISO-8859-1?Q?Christian_Ehrhardt=3A_IBM_Deutschland_?= =?ISO-8859-1?Q?Entwicklung_GmbH=2CVorsitzender_des_Aufsichtsrats=3A?= =?ISO-8859-1?Q?_Martin_Jetter=2CGesch=E4ftsf=FChrung=3A_Herbert_?= =?ISO-8859-1?Q?Kircher=2CSitz_der_Gesellschaft=3A_B=F6blingen=2CRe?= =?ISO-8859-1?Q?gistergericht=3A_Amtsgericht_Stuttgart=2C_HRB_243?= =?ISO-8859-1?Q?294?= User-Agent: Thunderbird 1.5.0.12 (X11/20080131) MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: linux-fbdev-devel@lists.sourceforge.net, linuxppc-dev@ozlabs.org, Andrew Morton , linux-kernel@vger.kernel.org, adaplas@gmail.com, Hollis Blanchard , Wolfgang Denk , Detlev Zundel Subject: Re: [PATCH 1/3] radeonfb: Fix 64 bits resources on 32 bits archs References: <20080422012723.BA9F2DE13F@ozlabs.org> In-Reply-To: <20080422012723.BA9F2DE13F@ozlabs.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Benjamin Herrenschmidt wrote: > This fixes radeonfb to not truncate 64 bits resources on 32 bits > platforms. Unfortunately, there are still issues with addresses > returned to userspace via struct fb_fix_screeninfo. This will > have to be dealt with separately. Thanks for this patch Benjamin, I use it together with what we have discussed in the "pci issue - wrong detection of pci ressources" thread. Unfortunately I now hit exactly that issue with fb_fix_screeninfo you describe. For everyone the fb_fix_screeninfo has two "unsigned long" vars that need to strore a IO address. This fails in my case with a 32bit powerpc system (=sizeof(long)=4) which has paddr >4Gb and actually it should affect any 32bit platform with paddr>4Gb. You see it e.g. when you try to initialize X11, the x11 radeon driver issues a FBIOGET_FSCREENINFO ioctl and because our address is >4Gb it get's clobbered by that unsigned long in the fb_fix_screeninfo structure (the value comes from a resource_size_t variable which has the correct 64bit). struct fb_fix_screeninfo { char id[16]; /* identification string eg "TT Builtin" */ unsigned long smem_start; /* Start of frame buffer mem */ [...] unsigned long mmio_start; /* Start of Memory Mapped I/O */ [...] I tried the stupid solution to just change the fb_fix_screeninfo structure to resource_size_t, but that changes the size ioctl transports and would require awareness in the userspace applications using that ioctl. The X11 & Framebuffer driver work on 64bit systems, so I think it's just an issue of not cutting that data down to 32bit when transporting it (has anyone already checked the x11 drivers, I hope they don't use unsigned long too). I wanted to ask if there are any known workarounds atm that would allow me to use my X11 for now? -- Grüsse / regards, Christian Ehrhardt IBM Linux Technology Center, Open Virtualization