Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262207AbVBVFKE (ORCPT ); Tue, 22 Feb 2005 00:10:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262208AbVBVFKE (ORCPT ); Tue, 22 Feb 2005 00:10:04 -0500 Received: from gate.crashing.org ([63.228.1.57]:27350 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S262207AbVBVFJ6 (ORCPT ); Tue, 22 Feb 2005 00:09:58 -0500 Subject: Re: POSTing of video cards (WAS: Solo Xgl..) From: Benjamin Herrenschmidt To: Jon Smirl Cc: Dave Airlie , dri-devel@lists.sourceforge.net, xorg@lists.freedesktop.org, Linux Kernel list In-Reply-To: <9e473391050221204215a079e1@mail.gmail.com> References: <4218BAF0.3010603@tungstengraphics.com> <21d7e997050220150030ea5a68@mail.gmail.com> <9e4733910502201542afb35f7@mail.gmail.com> <1108973275.5326.8.camel@gaston> <9e47339105022111082b2023c2@mail.gmail.com> <1109019855.5327.28.camel@gaston> <9e4733910502211717116a4df3@mail.gmail.com> <1109041968.5412.63.camel@gaston> <9e473391050221204215a079e1@mail.gmail.com> Content-Type: text/plain Date: Tue, 22 Feb 2005 16:09:20 +1100 Message-Id: <1109048960.5411.74.camel@gaston> Mime-Version: 1.0 X-Mailer: Evolution 2.0.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2270 Lines: 52 On Mon, 2005-02-21 at 23:42 -0500, Jon Smirl wrote: > On Tue, 22 Feb 2005 14:12:48 +1100, Benjamin Herrenschmidt > wrote: > > It's up to each driver to detect wether it's card need to be POSTed or > > not. Anything else would mean infinite breakage. > > Your approach is that it is a per driver problem. I was taking a > different tack and looking at it as a BIOS deficiency that should be > compensated for. There is already code in the kernel for identifying > the boot video device. Your assumption is rather specific to a given platform... what if you have a card with no ROM (embedded system) but your kernel has a copy of what should be the ROM at hand ? (flash is expensive, heh :) > I was working on the assumption that all PCI based, VGA class hardware > that is not the boot device needs to be posted. That isn't the case on all platforms. Also, I like the flexibility of having a userland helper since that doesn't "tie" us to the semantics of an x86 platform & BIOS (we could have an OF emulator too, or whatever binary program provided by the vendor in userspace to reinit the card without having to link that with the kernel). I think my approach is the most flexible in the long run. > And that the posting should occur before the drivers are > loaded. In order words the BIOS should have provided initialized > hardware but since it didn't we can apply a fixup in the PCI driver. I > also suspect there may be SCSI disk controller cards that need the > same procedure. I don't think we have to do these assumptions. It should really be under driver control. > I have no strong opinions on how to fix the post problem, I just want > to make sure the problem is fully discussed by the relevant people and > a consensus solution is achieved. I'm not sure that all of the core > kernel developers that might be impacted by this have considered all > of the options. I would like to try and get a consensus design and > avoid reimplementing everything ten times. Agreed. Ben. - 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/