Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268440AbUI2OMt (ORCPT ); Wed, 29 Sep 2004 10:12:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268372AbUI2OMs (ORCPT ); Wed, 29 Sep 2004 10:12:48 -0400 Received: from colossus.systems.pipex.net ([62.241.160.73]:50839 "EHLO colossus.systems.pipex.net") by vger.kernel.org with ESMTP id S268440AbUI2OMG (ORCPT ); Wed, 29 Sep 2004 10:12:06 -0400 Message-ID: <415AC2B3.6070900@tungstengraphics.com> Date: Wed, 29 Sep 2004 15:12:03 +0100 From: Keith Whitwell User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8a3) Gecko/20040817 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Discuss issues related to the xorg tree Cc: Christoph Hellwig , dri-devel , lkml Subject: Re: New DRM driver model - gets rid of DRM() macros! References: <9e4733910409280854651581e2@mail.gmail.com> <20040929133759.A11891@infradead.org> <415AB8B4.4090408@tungstengraphics.com> <20040929143129.A12651@infradead.org> <415ABA34.9080608@tungstengraphics.com> In-Reply-To: <415ABA34.9080608@tungstengraphics.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1469 Lines: 41 Keith Whitwell wrote: > Christoph Hellwig wrote: > >> On Wed, Sep 29, 2004 at 02:29:24PM +0100, Keith Whitwell wrote: >> >>> Christoph Hellwig wrote: >>> >>> >>>> - drm_flush is a noop. a NULL ->flush does the same thing, just easier >>>> - dito or ->poll >>>> - dito for ->read >>> >>> >>> Pretty sure you couldn't get away with null for these in 2.4, at least. >> >> >> >> Umm, of course you could. There's only a hanfull instance defining a >> ->flush at all. Similarly all file_ops for regular files and many char >> devices don't have ->poll. no ->read is pretty rare but 2.4 ch?cks it >> aswell. > > > I tried it, led to crashes (panics, I guess) & the change had to be > reverted. On reverting the crashes stopped. This was for poll and read: Thinking about it, it may not have been a problem of crashing, but rather that the behaviour visible from a program attempting to read (or poll) was different with noop versions of these functions to NULL versions, and that was causing problems. This is 18 months ago, so yes, I'm being vague. The X server does look at this file descriptor, which is where the problem would have arisen, but only the gamma & maybe ffb drivers do anything with it. Keith - 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/