Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268058AbUIKAr6 (ORCPT ); Fri, 10 Sep 2004 20:47:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268059AbUIKAr6 (ORCPT ); Fri, 10 Sep 2004 20:47:58 -0400 Received: from pimout5-ext.prodigy.net ([207.115.63.73]:6397 "EHLO pimout5-ext.prodigy.net") by vger.kernel.org with ESMTP id S268058AbUIKArx (ORCPT ); Fri, 10 Sep 2004 20:47:53 -0400 Date: Fri, 10 Sep 2004 20:47:36 -0400 (EDT) From: Vladimir Dergachev X-X-Sender: volodya@node2.an-vo.com Reply-To: Vladimir Dergachev To: Alan Cox cc: Dave Airlie , Jon Smirl , Felix =?ISO-8859-1?Q?K=FChling?= , DRI Devel , lkml , Linus Torvalds Subject: Re: radeon-pre-2 In-Reply-To: <1094853588.18235.12.camel@localhost.localdomain> Message-ID: References: <9e47339104090919015b5b5a4d@mail.gmail.com> <20040910153135.4310c13a.felix@trabant> <9e47339104091008115b821912@mail.gmail.com> <1094829278.17801.18.camel@localhost.localdomain> <9e4733910409100937126dc0e7@mail.gmail.com> <1094832031.17883.1.camel@localhost.localdomain> <9e47339104091010221f03ec06@mail.gmail.com> <1094835846.17932.11.camel@localhost.localdomain> <9e47339104091011402e8341d0@mail.gmail.com> <1094853588.18235.12.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2063 Lines: 48 Alan, I would like to disagree with you. On Fri, 10 Sep 2004, Alan Cox wrote: > On Gwe, 2004-09-10 at 23:19, Dave Airlie wrote: >> If the kernel developers can address this point I would be most >> interested, in fact I don't want to hear any more about sharing lowlevel >> VGA device drivers until someone addresses why it is acceptable to have >> two separate driver driving the same hardware for video and not for >> anything else.. (remembering graphics cards are not-multifunction cards - >> like Christoph used as an example before - 2d/3d are not separate >> functions...)... > > We've addressed this before. Zillions of drivers provide multiple > functions to multiple higher level subsystems. They don't all have to > be compiled together to make it work. > > 2D and 3D _are_ to most intents and purposes different functions. They > are as different as IDE CD and IDE disk if not more so. Functions - yes, but they become such only at a higher level. 3d for example does not really exist in kernel in any form. I would like to see unified fb (or the hardware-specific part of fb) and drm for one simple reason that I think you mentioned: One driver per device. I.e. one driver per *physical* device. Lastly, one point that you appear to have missed: DRM does DMA transfers (among everything else). FB sets video modes - i.e. messes with PLL. The problem is that there are configurations where messing with PLL while a DMA trasfer is active will lock up PCI (or AGP) bus hard. For example, a video decoder can be clocked off pixel clock for video pass through mode. If we trasfer video data to main RAM at the same time and FB gets a command instructing it to change resolution there would be a hard lockup. best Vladimir Dergachev - 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/